PHYSICS NUMERICALS - X

FORCE 

1) A rigid body is pivoted at a point. A force of 30 dyne acts on it at a distance of 65cm from the pivot, Calculate the moment of force.     1950 dyne cm

2) A force of 60N produces a moment of force of 12 Nm at a point on a rigid body. Calculate the distance between point of application of force and the turning point.  0.2m

3) A couple of 12 N force acts on a rigid body such that arm of couple is 60cm. Calculate the moment of couple in SI system.     7.2 N m

4) Calculate the resultant moment of the given body.

In which direction will the turning effect be ?      0,  As the resultant is zero , the body will not turn.

5) A metre scale is balanced at its midpoint by suspending two weights A and B of magnitude 50gf and 25 gf as shown in the figure.

Find the mark on the scale from where the weight B is suspended.   90cm

6) A uniform metre scale is balanced on a wedge placed under its 40cm mark at point O. At points A and B, weights of magnitude 60 gf and 20 gf, respectively, are suspended.

The scale is balanced by suspending a weight W at the point C. Calculate the value of W.    26.67 gf

7) The handle of a spanner is 25cm long and can tighten a nut if a force of 200 N is applied. if the magnitude of the force applied is 120 N, what is the length of the handle required to tighten the nut ?     0.41 m

8) A uniform metre scale is pivoted at its midpoint. A weight of 20 gf is suspended from one of its end of the scale. Where should a weight of 50 gf be suspended to keep the scale horizontal ?       70cm

9) The figure below

shows a balanced see-saw that is 4 m long and pivoted at the centre. A force of 40 N is applied at the end of the see-saw and another force F is applied at a distance of 1.6m from the opposite end on the other side of the privot.  Calculate the force F.    200 N

10) A uniform metre scale of weight 50 gf is balanced at 60cm mark when a weight of 15 gf is suspended at its 10cm mark. Where must a weight of 100 gf be suspended to balance the matter scale.     72.50 cm

FORCE 

1. Centrifugal force is an____ force.   

2. Moment of force is also termed as___.      

3. Pseudo force is also called as____.      

4. The algebraic sum give the ____ sum acting on the body.  

5. Force to the right of fulcrum acting downwards produces a ___moment.    

6. Weight of a body act at____of the body.    

7. ____ movements are considered as positive.    

8.  Centre of gravity is a___ point.        

Down 

9. Pair of force is acting on a door is called ____.      

10. Torque is the____ effect of force exerted on a beam that is pivoted at a point.     

11. Principle of moments is applicable only when the body is in____.   

12. In case of___ handles are placed at the extreme to have greater moment of force.   

WORK, POWER AND ENERGY 

1) A Work of 600 J is done when a force of 30 N is applied on the pedals of a bicycle. What is the distance through which the bicycle moves ?     20m

2) An elevator rises up to a height of 30m carrying passengers with a total mass of 600 kg.  Calculate the work done by the elevator.       -176400 J

3) A lawn mower is pulled with a force of 500 N directed at an angle of 60° with the ground. Calculate the work done by the mower when it is pulled to a distance of 50m.   12500 J

4) A force of 10N acting on a body at an angle of 60° with the horizontal direction displaces the body through a distance of 2 m along the surface of a floor. Calculate the work done. Now, let another force acting on the body making an angle of 30° with the horizontal do the same amount of work. What is the value of this force to displace the body through the same distance along the surface of the floor ? ( take cos60°= 1/2, cos30°= √3/2).        5, 5.77 N

5)  A man with a mass of 70kg runs up a flight of 40 stairs, each 15cm high in 30s. Find the power of the man. (g= 10 m/s²).       140 W

6) A rickshaw puller pulls the rickshaw by applying a force of 100 N. if the rickshaw moves with a constant velocity of 36 kmph, find the power of the rickshaw puller.    1000 W

7) The heart does a work 1.2 J in each heartbeat. How many times per minute does it beat if its power is 1.5 W ?       75

8) A horse exerts a force of 200 N to pull the cart. If the horse cart system moves with a velocity of 36 kmph on the level road, then find the power of horse in terms of horsepower (1 H. P= 750 W).      2.67 H. P

9) Calculate the horsepower of an engine that lifts 10 litres of water from a depth of 50m in 30 min. (Taking g= 10 m/s², density of water= 1000 kg/m³, 1 H. P= 750 W).            3693.33 H. P

10) An electric bulb of 100 W is used for 3 hours per day . Calculate the amount of energy consumed in 5 days.    5.4 x 10⁶ J

VARIOUS FORMS OF ENERGY AND CONSERVATION OF ENERGY 

1) Determine the kinetic energy of a roller coaster car with a mass 500 kg and moving with a velocity of 15 m/s.     5.625 x 10⁴ J

2) Energy of 6000 J spent in raising a suitcase of mass 50kg to a vertical height. Calculate the vertical height (take g= 10 m/s²).     12m

3) a body of mass 10 kg is taken from a height of 10m to 20 m. Calculate the increase in its potential energy. (Take g= 10 m/s²).     1000 J

4) A body of mass 2 kg falls from a height of 10m. Calculate the energy possessed by it at any instant of time. (Take g= 10 m/s²).     200 J

5) A body of mass 5 kg is initially at rest. A force of 20 N is applied on it. Calculate the kinetic energy of the body after 10s.      4000 J

6) A rock is dropped from a height of 40m. Determine the velocity with which it strikes the ground. (Take g= 10 m/s²).     28.28 m/s

7) Calculate the work required to be done to slow down a bus with a mass of 2000 kg moving at a velocity of 60 kmph to 36 kmph.     1.78 x 10⁵ J

8) A train weighing 5000 N has a kinetic energy of 10 kJ. Find the velocity of the train. (Take g= 10 m/s²).      6.32 m/s

9) How will the kinetic energy of a car change if

a) its mass is trippled.       Tripled

b) its velocity is doubled.     Four times 

c) its mass is doubled and velocity is halved?     Halved 

10) What will be the ratio r kinetic energy of two buses with equal mass moving with different velocities if velocity of bus A is 10 m/s and velocity of bus B is 12.25 m/s ?    2:3

11) A body mass 0.5 kg has a momentum of 30 kg m/s. Calculate the kinetic energy of the body.     900 J

12) An object of mass 10 kg is raised to a height of 20m above the ground level. What is its potential energy ? if the object is allowed to fall, find its kinetic energy when it is at a height of 5m above the ground. (Take g= 10 m/s).     200 J, 1500 J

13) A bullet of mass 3g travels with a speed of 600 M/s. It penetrates a wall that offers resistive force of 600 N to the motion of the bullet find 

a) the initial kinetic energy of the bullet.      540 J

b) the distance through which the bullet has penetrating before coming to rest.    0.9m

c) the speed with which the bullet emergence out of the wall if its thickness is 0.7m.   282.8 m/s

14) A body of mass 2kg is thrown vertically upwards with an initial velocity of 50 m/s. Calculate 

a) the initial kinetic energy impartu to the body.      2500 J

b) the maximum height if friction due to air is neglected.     125m

c) the maximum height reached if 25% of the initial energy is lost against air friction.   93.75 m

15) An oscillating simple pendulum rises to a maximum vertical height of 6 m at its extreme positions . if the mass of the bulb 300g, find 

a) the velocity of the bob at its resting position.      1.09 m/s

b) the total energy of the pendulum at any instant while oscillation (take g= 10 m/s²). Neglect the friction due to air.         0.18 J

MACHINE , LEVERS, PULLEYS

1) A machine has a mechanical advantage equal to 4. It raises a load of 20N. Calculate the mnimum effort that has been applied to it.      5N

2) An effort of 8 kgf is applied on a machine through a distance of 60cm when a load of 80 kgf moves through a distance of 4cm. Calculate 

a) velocity ratio.     15

b) mechanically advantage.      10

c)  efficiency of machine.     66.67%

3) Draw a simple diagram of 

a) wheelbarrow.

b) a plier and mark on it the fulcrum and points of load and effort. 

To which class of levers does each of these belongs.

4) A crowbar of length 150cm has its fulcrum at a distance of 25cm from the load.

Calculate the mechanical advantage of this crowbar.       5

5) To lift a piece of burning coal of mass 200g, a cook uses a fire tong of length 25cm. He applies the effort at a distance of 8 cm from its fulcrum. Find the effort applied by the cook.     (Take g= 10 m/s²).    6.25 N

6) The length of a nutcracker is 30 cm. A nut is kept 6cm away from the fulcrum and an effort of 30 N is applied at the other end of the nutcracker. Calculate the

a) resistance offered by the nutcracker.    150 N

b) Find the mechanical advantage.      5

7) The given diagram shows a lever in use.

a) To which class of lever does it belong ?     II lever 

b) if FA= 40 cm, AB= 60cm, find the mechanical advantage of the lever.      2.5

8) A mass of 200 kg drives a machine when it falls to a distance of 10 m in 5 s. The machine lifts a load of mass 800 kg vertically upwards. Calculate 

a) the work done by the falling mass in its displacement.  20000J

b) the power input provided to the machine.      4000W

c) the power output of the machine if its efficiency is 70%.   2800W

d) the work done by the machine in 5s. (Take g= 5 m/s²).   1400J

9) A woman draws water from a well using a fixed pully. The mass of the bucket and water together is 6 kg. The force applied by the women is 70 N. Calculate the mechanical advantage. (Take g= 10 m/s²).    0.857

10) A combination of a movable Pulley X with a fixed pully Y is used for lifting up a load of 20 kgf . Calculate the effort applied at the free end of the string, neglecting the weight of the pulley X and friction.      98N

11) In the figure,

a load of 500 N lifted by a man with the help of fixed pully through a height of 10m in 20s. The effort applied at the free end is 600N. Calculate 

a) the velocity ratio of the pulley.        The velocity ratio of a fixed is 1 as the distance moved by the load is equal to the distance moved by the effort.

b) the mechanical advantage,      0.833

c) the efficiency of the pulley.      83.3%

d) the energy gained by the load.        5000 J

e) the power developed by the man.       300W

12) A system of pulleyr with velocity ratio 4 is used to lift a load of 200 kgf through a vertical height of 15m. The effort required is 80 kgf in the downward direction. Calculate 

a) the number of pulleys in the system.     4

b) the distance moved by the effort.    60m

c) mechanical advantage .     2.5

d) efficiency of the pulley system.    62.5%

13) A block and tackle system consisting of 5 pulleys has three pulleys in the upper block and two pulleys in the lower block. if the load is raised by 1m, through what distance will the effort move ?      5m

REFRACTION OF LIGHT AT PLANE SURFACE 

1) The absolute refractive index of glasses is 1.5. Explain the statement.

2) The absolute refractive index of the alcohol is 1.37. Calculate the speed of light in alcohol.       2.19 x 10⁸ m/s

3) The refractive index of glass is 1.5 and that of water is 1.33. What is the refractive index of class with respect to water ?      1.127

4) A swimming pool appears to be 2m deep. How deep is it actually ? Refractive index of water is 1.3.     2.66 m

5) A small pin fixed on a tabletop is viewed vertically above from a distance of 30cm. By what distance would the pin appear to be raised if it is viewed from the same point through a 10cm thick glass slab held parallel to the table? Refractive index of the class is 1.5.    3.33cm

6) A fish is lying inside a pond. If viewed by a person from above the pond, the position of the fish will appear to be raised. Draw a diagram showing the position of the fish to the observer.   

7) If the three rays of light are incident normally on one of the faces of an equilateral prism, how will the rays remerge ?

8) An object PQ is placed before a right angled prism with critical angle 41°, as shown in the figure. Trace the path of the ray from P and Q passing through the prism and show the image formed.

9) Three rays of light A, B and C are incident at the point O which is the centre of a semicircle glass block at different angles of incidence such that angle of incidence for ray A< B < C.

If angle BON' is the critical angle, then draw the paths of all the three rays when they strike the edge XY at point O.

REFRACTION OF LIGHT THROUGH A LENS

1) Show with the help of a diagram, how an incident ray will emerge from a thick convex lens and a thin convex lens when it passes through the optical Centre ?

2) Two rays of light are incident on a thick concave lens as shown in the figure. Trace the path of these rays as they emerge from the lens and explain the diagram.

3) With the help of a diagram, show the converging action of a convex lens, considering it to be made up of a number of prism. Which rays deviate the most?

4) The figure given below

shows a refracted rays PQ from a convex lens. Draw the corresponding incident ray and complete the diagram.

5) The figure given below shows are refracted ray DD' from a concave lens.

Draw the corresponding incident ray and complete the diagram.

6) The figure given below shows two refracted rays DD' and OO' through a concave lens.

Complete the diagram showing the corresponding incident rays emerging from a point of an object placed on the principle axis. Where will the image of the object form?

7) The figure given below shows an object BA placed in front of a convex lens on the principal axis.

a) Draw the three principle rays to show the formation of image of the object.

b) What are characteristics of the image formed ?

c) if the object is moved a little distance away from its original position such that it lies at 2F₁, then where will the image be formed and what will be the size of this image ?

8) The figure given below shows an object AB and its image A'B' formed by a lens.

a) State the type of lens that will form this image.

b) Complete the ray diagram to show the formation of the image 

c) State the characteristic of the image.

9) The given figure shows an object AB and an image A'B' formed by a lens.

a) Locate the lens and mark the focus of the lens. What type of lens will produce this type of image?

b) Complete the ray diagram.

10) A convex lens can act as a burning glass. Draw a ray diagram showing how it can be achieved.

11) A convex lens of focal length 5cm is placed at a distance of 6cm from a wall. How far from the lens should an object be placed so as to from its real image on the wall ?

12) An object is placed perpendicular to the principal axis of a convex lens of focal length 6cm. The distance of the object from the lens is 8cm. Find the distance of image from the lens.      +24 cm

13) A convex lens forms the image of an object kept at a distance of 20cm in front of it,  a distance of 10cm on the side of the object. Find the nature the image and focal length of the lens.    -20cm

14) A concave lens has focal length 18cm. At what distance should the object from the lens be placed so that it forms and image at 12 cm from the lens.     -36 cm

15) The magnification produced by a spherical lens is +0.5 what is the 

a) nature of the lens ?

b) nature of the image ?

16) A lens has a power of + 2.0D.  What is the focal length and nature of the lens?   0.5m

THE ELECTRO MAGNETIC SPECTRUM 

1) A light composed of red and blue colour is incident on 

a) a single prism 

b) a glass slab 

c) on a prism A kept near another inverted prism B, as shown in the figure. 

Complete the diagram by showing emergent rays in each case.

2) A beam of white light is incident on a prism A, such that a spectrum is obtained upon dispersion through it on a screen PQ kept on the other side of the prism . The screen has a narrow aperture so as to allow only yellow light to pass through it. Prism B (same orientation as A) and a screen P'Q' are placed near the screen PQ. Draw a diagram to illustrate this.

3) A beam of light is incident normally on the face AB of an isosceles right-angled triangle as shown in the figure. Complete the diagram and show the emergent ray if the light is composed of 

a) yellow and Orange colour

b) yellow and green colours. Consider the critical angle for glass air interface for yellow light to be 45°.

SOUND, WAVE, VIBRATIONS & RESONANCE 

1) The wavelength and frequency of a sound wave in a certain medium is 25cm and 1500 Hz. Keeping the same medium, if the wavelength is changed to 30cm, calculate

a) the velocity of sound.    375 m/s

b) new frequency.      1250 Hz

2) A sound wave has a frequency of 3 kHz and a wavelength 50cm. How long will it take for the wave to travel a distance of 2km ?      1.33s

3) An echo is heard in 3s after the emission of sound. if the speed of sound in air is 340m/s, what is the distance of the reflecting surface from the source ?   510m

4) a man start 70m in front of a large wall and claps about 31 times after each successive echo. If the total time taken for these numbers of clasps is 12.5 s, calculate the speed of sound .     336 m/s

5) a boy stands between two parallel cliffs and fires a gun. He hears two successive echoes, one after 2s and the other after 4s. Calculate the distance between the two cliffs . Take Speed of sound in air as 330 m/s.         990m

6) A person is standing between two parallel cliffs that are separated by a distance of 1000m. He claps his hands and hears the first echo after 2s. If the speed of sound is 330 m/s, after how much time will he hear the second echo?      4.06s

7) A man standing in front of a cliff fires a gun. An echo is heard after 5s. On moving 85m closer to the cliff, he again fires a gun and hears an echo after 4.5s.  Calculate 

a) the distance of man from the cliff to his initial position.    850

b) the speed of sound,       340 m/s

8) A Sonar device on a submarine sends out a signal and receives an echo about 3s later. if the speed of ultrasonic waves in water is 1450 m/s, find the distance between the submarine and the reflecting object.     2175m

9) The stem of a vibrating tuning fork is pressed against a hollow matchbox and a hollow shoebox.

a) Name the type of vibration that the tuning fork sets these boxes to.

b) In which box will the sound be louder?

c) if an exactly similar vibrating turning fork is brought close to this fork, what will be the effect ?

10) A tuning fork vibrates with a natural frequency of 512Hz. If two strings, one of frequency 256 Hz and the other of frequency 512 Hz, are brought in the vicinity of this tuning fork, what would be the effect in each case ?

11) A vibrating trning fork is placed over a mouth of a burette that is fully filled with water. Its stopcock is opened and water is allowed to fall gradually. What would be the possible observation?

12) Study the adjoining diagram

representing a musical note. Redraw the diagram for a note 

a) with a higher pitch

b) that is louder.

13) The figure below shows

displacement-distance graph for three different sounds. Among these 

a) which sound has the highest pitch ?

b) Which is the loudest sound ?

c) What is the ratio of wavelength of sound A to sound B ?

d) How do the three sounds differ in quality ?

14) A person is listening to a song on a radio. At a point in the song, the singer hits a particular note and the person guesses the wavelength of that note to be 15 mm. Is this guess correct? Explain. 

CURRENT ELECTRICITY 

1) A conductor of resistance 4 Ω can pass a current up 2.5 A through it. Calculate the potential difference required across the conductor.        10V

2) Calculate the amount of work done in moving a charge of 5 C through a potential difference of 25V. What will be the potential difference if this amount of work is done in moving a charge of 10C ?       12.5V

3) A metallic wire of length 1m is stretched to double its length in such a way that there is no change in density of the wire . Calculate the ratio of the final resistance.     1:4

4) A wire of length 15m and uniform cross section of 6x 10⁻⁷m² has a resistance of 5Ω. Calculate the resistivity of the material of the wire.    2 x 10⁻⁷Ωm

5) When a potential difference of 4V is applied across the ends of a wire of 10m length, a current of 2A flows through it. Calculate 

a) the resistance per unit length of the wire.     0.2Ω m⁻¹

b) the resistance of 4m length of this wire.      0.8Ω

6) A battery supplies a current of 0.8 A through a 2Ω resistor and a current of 0.4A through a 5Ω resistor. Calculate the internal resistance of the battery.     1Ω

7) What will be the equivalent resistance of three resistors of 4Ω, 8Ω and 16 Ω if these are connected in 

a) series.    28Ω

b) parallel.      2.28Ω

8) A lamp of resistance 800 Ω, a fire alarm of resistance 30 Ω and a vacuum cleaner of resistance 200Ω are connected in parallel to the mains supply of 240 V. Calculate the current through each appliance and the total current supplied by the mains.    9.5A

9) The effective resistance of two resistors is 25Ω. If the resistance of one of the resistors is 10 Ω, what is the resistance of the other resistors ?     15Ω

10) The effecttive resistance of three resistors connected to a battery is 5 Ω. If R₁ = 10Ω, R₂ = 15Ω, what will be the value of R₃ ? Draw a circuit diagram with the flow of current across each resistor.      30Ω

11) A parallel pair of resistors of values 4Ω and 12 Ω are together connected in series with another resistors of value 3 Ω and battery of emf 24 V. Draw a circuit diagram and calculate the current across each resistor .        3A, 1A

12) The figure below shows

V-I graphs of two metallic conductors for series and parallel combination. Which graph represents parallel combination ?

13) The lengths of three conducting wires of same materials are in the ratio 1:2:3. The area of cross section of each wire is same, if these wires are joined in parallel across a battery, what will be the ratio of the currents in them ?     6:3:2

14) In the given circuit diagram,

the emf of the cell is 5 V and its an internal resistance is 2.5 Ω. Calculate the current flowing in the circuit.    0.67A

15) Find the current flowing through the given circuit connected to a cell of supply 5V. 

  3.75A

16) From the circuit flow diagram given below,

Calculate the current flowing through the circuit.      0.67A

17) Three resistors of 8Ω, 4 Ω and 2 Ω are connected together in such a way that the total resistance is greater than 8Ω but less than 10 Ω. Suggest a suitable arrangement of how these resistors can be possibly combined and calculate the total resistance.    9.33Ω

18) In the given diagram,

A₁, A₂ and A₃ are three ammeters of negligible resistance. The reading of ammeter A₃ is 1A. Calculate 

a) the readings of ammeter A₁ and A₂.    3A

b) the total resistance of the circuit.     2Ω

19) The diagram below

shows three resistors of 5Ω, 8Ω and 10Ω connected to a battery of emf 10V. Calculate 

a) the potential difference across the parallel resistors 8Ω and 10Ω.   4.7V

b) the current through 8Ω resistors.   0.59A

20) A cell of emf 2.5 V and internal resistance 1.5 Ω is connected to resistors of 5 Ω and 15Ω in series. Draw a circuit diagram and calculate 

a) the current in the circuit.   0.116A

b) the potential difference across each resistor.    1.74V

c) the total potential difference across the cell.     2.32V

21) An electric motor draws a current of 5 A from a 220V line. Determine the power of the motor and the energy consumed in 2 hour.   7.92 x 10⁶J

22) A heater has a power of 1.1 kW at 220V.

a) Find the resistance of the heater.   44Ω

b) Calculate the energy in kWh consumed in a week if the heater is used daily for 4h.    30.8 kWh

23) An electric heater draws 5A of current for 10 minute when connected to 230V power supply. Find the heat energy developed.      690 kJ

24) Find the current flowing through an electric bulb rated as 100W, 220V when connected to a 110 V supply. What will be the power consumed now?    25W

25) Three bulbs, A, B and C, are connected in parallel across 110V source . The rating of bulb is 5oW, 110V,  bulb B is 20W,110 V and bulb C is 100 W, 110V

a) Calculate the current flowing in each bulb.  0.45A, 0.18A, 0.9A

b) Which bulb will glow the brightest ?    C

26) Two resistors with resistance R₁ = 5Ω and R₂=7Ω are connected in series across a battery of emf of 16V. Draw a circuit diagram and find

a) the electrical energy consumed by each resistor in 30 second.265.33J, 371.47 J

b) total power developed in the circuit.      21.28 W

27) In the previous example, if the resistors are connected in parallel instead of series, what would be the electrical energy consumed by each resistor. Draw a circuit diagram for the same.    1536 J, 1097.14 J

28) two bulbs are rated as 40W, 220 V and 40W, 110 V,  respectively. Compare the resistance of two bulbs.    4:1

29) A geyser is rated 1.5kW, 250V. It is connected to 250V mains. Calculate 

a) the current drawn by the geyser.     6A

b) electrical energy consumed in 10h in joules.     54 x 10⁶ J

c) cost of energy consumed at Rs3.50 per kWh.      Rs52.50

30)  Four tube lights of 40 W each, two fans of 100W each and three bulbs of 60W each operate on an average of 8h per day. If the cost of energy is Rs2.50 per kWh, calculate the monthly bill.      Rs324

ELECTROMAGNETISM 

1) A straight vertical wire passes through the centre of a horizontal cardboard on which some iron fillings are sprinkled. Plot the directions in which the iron fillings will align themselves when the wire carries an electric current

a) in the upward direction

b) in the downward direction.

2) A circular coil penetrates a horizontal cardboard at two diematically opposite points. If the coil carries the current a current in the clockwise direction from the viewing end, Plot the direction of magnetic field lines along the horizontal plane of the cardboard.

3) A circular coil of radius 10cm, 50 turns, carrying a current of 2A has a magnetic field strength of X. Will the magnetic field strength be less than, equal to or more than X if

a) radius is 20 cm

b) number of tunrs are 75 

c) current passing is of 5A?

4) In the given figure,

P and Q are two straight conductors carrying current of equal strength in opposite direction as shown . O is a point located midway between the two conductors.

a) Draw the pattern of magnetic field lines around the conductors P and Q.

b) What will be the direction and strength of magnetic field at a point O ?

c) How will you prove that the direction of magnetic field drawn by you around the point O is correct ?

d) What will be the magnetic field at point O if current is in conductor Q is reversed?

5) Which of the electromagnets in the figure given below

will produce the strongest magnetic field if the strength of current is equal in each case ? Explain your answer.

6) The given figure

shows a rectangular coil ABCD connected with a commutator and a battery between its ends A and D and is placed between the pole pieces of strong magnet.

a) State the direction of current flowing in the coil.

b) What is the direction of force on each arm of the coil ?

c) What will be the direction of rotation of the coil ?

d) What will be the effect if the terminals of the battery across A and D are interchanged?

7) The given figure shows the diagram of a commutator.

a) Label its parts 

b) State the functions of its parts.

8) State the effect if 

a) the area of cross-section of the coil of a DC motor is decreased?

b) the strength of current passing through the coil is increased 

c) the direction of current through the coil is reversed.

9) State the functions of the following in a DC motor 

a) battery

b) armature coil 

c) horseshoe magnet

d) commutator.

10) The given figure shows a coil connected to a sensitive galvanometer G and a magnet NS placed closed to it.

a) What will you observe if the magnet is dropped into the coil ?

b) What will be the observation if the magnet is taken out of the coil ?

c) What will be the effect if the number of turns in the coil is decreased ?

11) The given figure shows two coils A and B wound around the soft iron core.

a) State the polarity at end P and end Q when switch S is closed.

b) What is the effect in the galvanometer attached to coil B when the switch S is closed ?

c) What will be the effect if resistance R is reduced and then switch is closed?

d) What will be observed if coil B is moved away from coil A with the switch closed ?

12) The given figure shows

a coil A wound around a soft iron core with its terminals connected to an AC source through a lamp A and a switch S. Another coil B wound around an iron core has a lamp B connected to its terminal and is displaced close to coil A. 

a) What will happen in coil A when the switch is closed ?

b) What will be the effect on coil B ?

c) Will the lamp B glow constantly ?

13) a) Draw a simple labelled diagram of a step of a step-up transformer.

b) On which principle a transformer work?

c) Can a. transformer work with DC source ?

14) a) Draw a simple schematic representation of the circuit of a step-down transformer.

b) What is the function of a step-down transformer ?

c) What is the turn ratio of a step-down transformer ?

15) At the generation station, voltage is generated at 11 kV and then it is stepped up to 132 kV. If the input power and output power is same equal to 11 kW, calculate turns ratio, input current and output current.

16) If the voltage at mains supply to 220V and an electric bell requires 11 V to operate, which type of transformer should be used ? Also calculate its turns ratio.

HEAT 

1) To raise the temperature of a substance by 15°C, the amount of heat energy required is 3500J. Calculate the heat capacity of the substance.      233.33 J/K

2) A 1000 calculate of heat energy is required to raise the temperature of 0.060 kg of a liquid from 10°C to 50°C. Find the specific heat capacity of the liquid 

a) in kcal kg⁻¹°C⁻¹.     0.416 kcal kg⁻¹°C⁻¹

b) in Jkg⁻¹K⁻¹.     1750 J kg⁻¹K⁻¹

3) Calculate the heat energy required to raise the temperature of 500g of copper from 30°C to 50°C. Take specific heat capacity of copper as 400 J kg⁻¹K⁻¹.    4000 J

4) An electric immersion rod is switched on for 5 minutes. The heat supplied by it raises the temperature of 1 kg of water from 30°C to 90°C. Calculate 

a) the power of heater.      840 J s⁻¹ or 840 W

b) heat capacity of water, if the specification heat capacity of water is 4.2 Jg⁻¹°C⁻¹.   4200 JK⁻¹

5) The temperature of 250g of water rises by a certain value, when some amount of heat is supplied to it. When the same amount of heat is supplied to 125g of kerosene oil, its tempreture rises by four times the temperature rise of water. If the specific heat capacity of water is 4200 J kg⁻¹K⁻¹, calculate the specific heat capacity of kerosene oil.       2100 Jkg⁻¹K⁻¹

6) A 100g of water at 70°C is poured into a beaker containing 60g of water at 20°C. The final temperature of the mixture is 35°C. If the specific heat capacity of water is 4.2 Jg⁻¹K⁻¹, calculate the thermal capacity of the beaker.      728 JK⁻¹.

7) Some amount of hot water is poured in a vessel containing cold water at 10°C temperature whose mass is three times the mass of hot water. The final equilibrium temperature is formed to be 30°C. Calculate the temperature of hot water. Neglect the heat energy abserbed by the vessel.        90°C

8) A solid of mass 50g is heated to a temperature of 80°C. It is dropped into a copper calorimeter containing 150g of water at 20°C. The mass of calorimeter is 50g and the specific capacity of copper is 0.4 Jg⁻¹K⁻¹. The final temperature of the mixture after stirring in 30°C. If the specific heat capacity of water is 4.2 JgK⁻¹, find the specific heat capacity of the solid.        2.6 Jg⁻¹K⁻¹

9) A liquid A of specific heat capacity 1600 Jg⁻¹K⁻¹ at 80°C is mixed with a liquid B of specific heat capacity 900 Jg⁻¹K⁻¹ at 30°C. The final temperature of the mixture is 50°C. Calculate the ratio of masses of the liquid.     3:8

10) A hot cube of iron of mass 200g is dropped into 600g of water at 20°C. The final temperature attained is 40°C.  Calculate the temperature of the hot ball. Specific heat capacity of iron is 0.483 Jg⁻¹K⁻¹ and specific heat capacity of water is 4.2 Jg⁻¹K⁻¹.    561.74°C

11) The graph given below represents the heating curve of a substance that starts as a with solid below its present point.

a) What is the melting point of this substance ?    

b) Which process is represented by the line segment DE of the curve ?    

c) In which line segment is the average kinetic energy increasing ?

d) What is happening to the average kinetic energy of the molecules in part BC of the curve ?

e) What is the boiling point of the substance ?

12) the graph given below shows two curves, one for water and the other for benzene of same mass, with variation of temperature with amount of heat supplied.

a) Calculate approximately the latent heat of fusion of water and benzene.   200 Jg⁻¹

b) Calculate approximately the latent heat of vaporization of water and benzene.   400 Jg⁻¹

c) Calculate approximately the specific heat capacity of a benzene.      1.33 Jg⁻¹°C⁻¹

13) if the specific latent heat of paraffin wax is 146 Jg⁻¹, how much amount of heat will be required to melt 1.5kg of paraffin wax?      219 kJ

14) Calculate the quantity of heat required to convert 2 kg of ice at 0°C to water at 15°C. (Specific latent heat of ice =336 Jg⁻¹, specific heat capacity of water 4.2 J g⁻¹°C⁻¹).    798 kJ

15) A piece of metal at 10°C has a mass of 50g. When it is immersed in a current of steam at 100°C, 0.7g of steam is condensed on it. Calculate the specific heat of metal.     0.084 cal g⁻¹°C⁻¹

16) A 30g ice cube at 0°C is dropped into 200 of water at 30°C. Calculate the final temperature of water when the entire ice cube has melted.  Take: Latent heat of ice= 80 cal g⁻¹, specific heat capacity of water = 1 cal g⁻¹C⁻¹.     15.65°C

17) A 500g of ice slab at 0°C is provided with heat energy at a constant rate. It gets converted to water in 4 minutes. Calculate the time required to raise the temperature of water from 0°C to 80°C. Take specific latent heat of ice =336 Jg⁻¹, specific heat capacity for water = 4.2 J g⁻¹K⁻¹.          4 min

18) A 20 kW electric heater with 60% efficiency is used to melt 400g of ice at 0°C. calculate the time required by the heater to do so if the specific latent heat of ice is 336 Jg⁻¹.        11.2s

19) How much amount of ice will melt if 300g of ice at 0°C is mixed with 400g of copper strips at 400°C ? What is extra amount of heat energy needed to melt the whole of ice ? (specific heat capacity of copper =0.4 J g⁻¹K⁻¹, Latent heat of ice= 336 Jg⁻¹).            36800 J

20) A vessel of negligible heat capacity contains 60g of ice in it at 80°C. 100g of water at 80°C is passed into the ice to melt it.

a) Find the amount of heat absorbed by ice to melt into water at 0°C.    20160 J

b)  Find the final temperature of the contents of the vessel. (specific latent heat of fusion of ice =336 Jg⁻¹, specific heat capacity of water = 4.2 J g⁻¹C⁻¹).    20°C

21) In a laboratory experiment for finding the specific latent heat of ice, 100g of water at 30°C was taken in a calorimeter made of of copper of mass 10g. When 10g of ice at 0°C was added to the mixture and kept within the liquid until the ice melted completely, the final temperature of the mixture was found to be 20°C.

a) What is the total quantity of water in the calorimeter at 20°C ?     110g

b) If specific heat capacities of water and copper are 4.2 Jg⁻¹C⁻¹ and 0.4 Jg⁻¹C⁻¹, respectively, what quantity would each calorimeter and water release in cooling down to 20°C from the initial stage?     40 J

c) Calculate the heat gained by ice on melting.      4240 J

d) Calculate the value of the latent heat of fusion of ice from the data discussed above.    340 Jg⁻¹  

MODERN PHYSICS 

1) From the following elements, choose the atoms that are

a)  isotopes

b) isobars

c) isotones : ¹²₆C , ¹³₆C, ¹⁴₆C, ¹³₇N, ¹⁴₇N.

2) What is the effect of freezing a radioactive element on the radiations emitted by it ?

3) Compare γ-rays with UV rays.

4) An element X has a mass number 40 and atomic number 19.

a) Write the symbolic representation of the element.

b) What are the number of protons, electrons and neutrons in it ?

c) Write an equation if the element undergoes a β-emmission reaction.

5) State the properties that are common to α, β and γ radians.

6) Complete the table complete below :

Change in property of elements 

α-emmission

β-emmission

Positron emission 

γ-emmission

Their a) Mass number b) atomic number 

7) The nucleus of a thorium atom ²³⁴₉₀Th undergoes several α and β disintegrations and ultimately decays to form a lead atom ²⁰⁶₈₂Pb. Calculate the number of α and β particles emitted.

8) Complete the following equations of radioactive disintegrations:

X-----ᵅ-->X₁---ᵝ-->X₂---->ᵞ-->X₃---ᵝ--->²³⁴₉₂X₄.

9) An element A undergoes two α-decays and the daughter elements B undergoes a β-decay forming an element C, The element C is in an excited state and undergoes a γ-radiation to form element D. Represent the series in the form of an equation.

10) State tro harmful and two beneficial effects of radioactivity for human beings.

FORCE

PREVIEW 

FORCE (Multiple choice questions)

1) Moment of force is ____proportional  to the distance of point of application of force and fulcrum 

a) inversely b) directly c) not d) none 

2) Lessor the force applied____ is the moment of force.

a) greater b) lessor c) equal  d) none

3) Clockwise moments are considered to be____.

a) positive b) negative c) zero d) all of these

4) _____moments are considered to be positive.

a) clockwise b) anticlockwise c) total  d) none

5) For equilibrium ____ sum of moments is equal to _____ sum of all anticlockwise moments.

a) arithmetic, arithmetic 

b) algebraic, algebraic 

c) total, none of  d) all of these 

6) The weight of an object lies at the____

a) Centre of mass b) centre of buoyancy c) centre of gravity d) geometric centre always.

7) The CG of a regular object would lie__

a) on the body  b) outside of the body c) inside the body  d) all of these 

8) The CG of a regular object will depend on ____

a) distribution of mass.

b) volume of the body.

c) density of the body d) all of these

9) Longer the size of the key___ it is to open a safe vault .

a) easier b) convenient 

c) lesser the force required by 

d) none of the above

10) Huge trailer trucks have their steering wheel of ____diameter 

a) large b) small c) least d) all of these

11) Can a couple pair of forces keep the body in equilibrium 

a) yes b) no c) data insufficient d) none

12) Centre of gravity is ___when it is a hollow cone.

a) raised from the base

b) lower towards the base 

c) centre of the vertical axis d) non

13) C. G of a solid and hollow sphere are ___

a) the same  b) different c) almost the same d) geometric centre 

14) uniform circular motion has____

a) constant speed and variable velocity

b) variable speed and constant velocity

c) circular motion with uniform speed

d) none of these 

15) uniform linear motion has____

a) constant speed, variable velocity

b) constant speed, constant velocity

c)  variables speed , constant velocity

d) variable speed, variable velocity

16) When a body moves in a circular path, inward seeking force is called ___

a) Centrifugal force b) tension force c) tangential force d) centripetal force

17) When a body moves in a circular path, outward force is called a ___

a) pseudo force 

b) centrifugal force 

c) centripetal force 

d) reaction force 

18) For a body to perform uniform circular motion, ____

a) centrifugal force is equal to the centripetal force 

b) centrifugal force is less than centripetal force 

c) centripetal force is less than centrifugal force 

d) centripetal and centrifugal forces cancel each other.

19) Find the maximum force required to open a nut by a spanner of length 50cm producing a torque of 50Nm ?

a) 10N b) 100N c) 0.1N d) none

20) 100 dyne cm is equals to___Nm.

a) 10⁵ b) 1/10⁵ c) 0 d) 0.001

21) 10⁻¹⁰ Nm is equal to ___dyne cm.

a) 10⁻⁴ b) 10 c) 0.001 d) none 

22) Find the weight of half metre scale balanced at 5cm mark when of 10gf is suspended at one of its ends.

a) 2.5 gf b) 100gf c) 0.2gf d) 50gf

23) Find the resultant moment of couple if two equal forces each of 6N are acting at a distance of 3cm each from the centre.

a) 36Nm b) 360Nm c) 3.6Nm d) 0.36Nm

24) centripetal force is____ while centrifugal force is ____

a) real, real b) real ,virtual c) virtual real d) virtual virtual 

1b 2b 3b 4b 5b 6c 7d 8a 9c 10a 11b 12a 13c 14c 15b 16d 17b 18a 19b 20b 21c 22a 23d 24b

Fill in the blanks 

1) Centrifugal Force is an_____.         Outward 

2) Moment of force is also termed as _____.      Torque 

3) Pseudo force is also called as____.          Fictitious 

4) The Algebraic sum give the___ sum acting on the body.        Net

5) Force to the right of fulcrum acting downwards produces a ____moment.     Clockwise 

6) Weight of body acts at ____ of the body.     Centre of gravity 

7) ____ moments are considered as positive.         Anticlockwise 

8) Centre gravity is a ______point.            Imaginary 

9) Pair of forces acting on a door knob  is called ____.         Couple 

10) Turque is the _____effect of force exerted on a beam that is pivoted at a point.     Rotational 

11) Principle of moment is applicable only when the body is in____.       Equilibrium 

12) In case of____ handles are placed at the extreme to have greater moment of force.         Window 

Very Short Questions

1) What is meant by rotational motion ? How is it different from translational motion ?

2) Give few examples of rotational motion.

3) Define moment of force.

4) Write the relationship between the SI and CGS unit of moment of force.

5) Is moment of a force scalar or a vector quantity?

6) Name the factors affecting the turning effect of a body ?

7) State the gravitational units of torque.

8) If the moment of force is assigned a negative sign, then will the turning tendency of the force be clockwise or anticlockwise?

Clockwise 

9) Will a door open if a force is applied on its hinges ?

10) Why is the handle of a door provided at its free end away from the hinges?

11) If one light and one heavy person sit on a see-saw, what should be their positions to maintain a balance or equilibrium around the fulcrum?

The heavier person needs to sit closer to the fulcrum as compared to the lighter person, on the opposite side.

12) Which of these would be easier to turn: a steering wheel of small diameter and a steering wheel of large diameter ?

Large diameter 

13) why does a wrench has a long handle ?

14) In the diagram given below, a force F is applied on a bicycle tyre at two different points are shown in the figure A and B. Which of these wheels will have a more turning effect ? if the two wheels need to have equal turning effect, how should the force be changed ?

Wheel A, as the perpendicular distance between the turning points and point of application of force is more. To have the same turning affect, the magnitude of force needs to be increased on wheel B.

15) In the figure below A, B, C and D are forces of equal magnitude around a point O. The distance of forces A, B, C and D from point O are 3cm, 7cm, 1.5cm  and 4.5cm, respectively . Among these forces ,

a) Which force has the greatest moment about point O?

b) Which force has the smallest moment about the point O ?

Force B, due to maximum perpendicular distance.

Force C, due to the least perpendicular distance

16) The position of centre of gravity of a body remains unchanged even when the body is deformed. Is the statement true or false ?    False 

NUMERICAL PROBLEM 

1) A force of 5N is applied at a perpendicular distance of 0.2m from a pivoted point. Calculate the moment of force.           1 Nm

2) The moment of force of 8N about a fixed point is 4Nm. Calculate the distance of the point from the line of action of force.     0.5m

3) A nut can be opened by a wrench of lengths 50cm with a force of 120N. If a smaller force of 75N is applied, what will be the required length of the handle of the wrench?    80cm

4) In the figure, a bicycle wheel of circumference 8m is shown. A force of 4N is applied at the point P in the direction shown. Calculate the moment of force at

a) point O.      5.09m in anticlockwise direction 

b) point Q.      10.18m in anticlockwise direction 

5) Two forces of equal magnitude are acting on a uniform bar AB of length 6m, which is pivoted in the centre of shown in the figure. Determine the magnitude of moment of force. 

a) at the end A.         15N m anticlockwise 

b) at the end of B.       15N m anticlockwise 

c) total amount moment of couple.     30 N m anticlockwise 

6) Two forces F₁=5N and F₂ = 8N are acting at points P and Q of a rod pivoted at a point O such that OP= 8m and OQ= 2m.

Calculate the

a) moment of force F₁ at point O,        40N m anticlockwise 

b) moment of force F₂ at point O.      16 N m clockwise 

c) total moment of the two forces at point O.     24 N m anticlockwise 

7) A uniform meter scale is balanced at 60cm mark, when weights of 5gf and 40gf are suspended from 10cm mark and 80cm mark, respectively. Calculate the weight of the meter scale.       55 gf

8) A uniform metre scale weighing 100gf is pivot at a point O, a 25cm mark. A 80gf weight is hung from 10cm mark and a 30gf weight is hung from 70cm mark as shown in the figure.

Calculate 

a) the total anticlockwise moment about point O.     1200 gf cm

b) The total clockwise moment about point O.     3850 gf cm

c) the net resultant moment.     2650 gf cm anticlockwise 

9) A uniform metre scale of mass 50g is balanced on the edge of a knife at mark 60cm by suspending an unknown mass at the 80cm mark. Find the value of the unknown mass.        25g

10) A see-saw of 8m long is balanced in the middle. Two children of mass 30kgf and 40 kgf are sitting on the same side of the fulcrum at a distance of 1.5m and 3.5m respectively, from the fulcrum. At what distance must an adult person of weight 60 kgf sit from the fulcrum so as to balance the see-saw?     3.08 m from fulcrum on the opposite side of children.

11) A uniform metre scale of weight 20gf is pivoted at its zero mark. Calculate 

a) the moment of force that depress the scale .       1000 gf cm

b) what would be the magnitude of least force applied on it to make it horizontal?     10 gf force upwards at the 100 cm mark 

12) A uniform metre scale can be balanced at the 70cm mark when a mass of 0.05kg is hung from the 94cm mark 

a) Draw the diagram of the arrangement

b)  Find the mass of the metre scale.    0.06 kg

13) A red bull tin is to be opened by means of a screwdriver as shown in the figure. Find the minimum effort required to flick open the lid ?      3.48 N

FORCE - TEST

Time: 30 minutes      Marks: 20

Section 1

(All questions are compulsory)

1)a) Define moment of force and state its SI unit.    (2)

b) Screw jack is provided with a longer arm. Why?   (2)

c) State the principle of moments as applied to a beam in equilibrium .   (2)

d) Differentiate between centripetal force and centripetal force.   (2)

e) A nut is opened by a spanner of length 10cn. If the least force required is 10N.

   Find the moment of force required to turn the nut.      (2)

Section 2 

(Attempt any one question out of two)

2a) The figure shows two forces F₁ = 5N and F₂= 3N acting at points A and B of a rod pivoted at a point O such that OA= 2m and OB= 4m.

Calculate 

i) The moment of force D₁ about point O

ii) The moment of force F₂ about point O

iii) The total moment of two forces about O.       (3)

b) Define the term Couple. State its mathematical relation and also stated its SI unit.   (3)

c) State the position of centre of gravity for the following objects:

i) scalene triangle

ii) Hollow ring 

iii) solid cone

iv) solid cylinder      (4)

3a) A uniform metre scale is balanced at 60 cm mark such that two weight one of 5 gf  and another 40gf are suspended 10cm mark and 80cm mark respectively. Calculate the weight of the metre scale.    (3)

b) A stone of mass m kg is rotated in a circular path with uniform speed by tying a strong string with the help of your hand. Answer the following questions :

i) is the stone moving with uniform or variable speed ?

ii) is the stone moving with uniform acceleration?

iii) in which direction does the acceleration act?

iv) What kind of force acts on the hand? State its direction.     (4)

c) A boy of mass 30kg is sitting at a distance of 2m from the middle of the see-saw.

Where should a boy of mass 40 kg sit so as to balance the see-saw?    3

MACHINE 

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double the diagram below shows a fully arrangement copy the diagram and mark the direction of the tension on its trend of the string what is the velocity ratio of the arrangement if the tension acting on the string is then what is the relationship between and effort if the free and of the string moves through a distance at find the distance by which the load is rest 

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WORK, POWER AND ENERGY 

1) Work done = force x _____

a) distance b) time c) velocity  d) displacement 

2) SI unit of work is ____

a) newton b) joule c) erg d) dyne

3) 1 dyne cm= ____

a) 1 erg b) one newton c) 10 newton cm d) none 

4) work done is a _____quantity.

a) pure  b) scalar c) vector d) dimensionell

5) Work done is positive when ____

a) distance is positive  

b) maximum distance travelled along direction of force applied

c) displacement is in direction of force applied 

d) distance is negative 

6) Work done by buoyant force is___

a) positive  b) negative c) zero d) cannot definitely say

7) a parrot flying at a height of 300m above sea level applying a force of 10N___

a) does no work  b) does work equal to 3000 J c) does negative work d) none 

8) A spprinter running in a 200m x 4 medley relay circular track does not do any work. Is this statement always true?

a) yes b) no c) incomplete data d) none

9) 1J= ___kWh.

a) 3.6 x 10⁶ b) 0.278 x 10⁻⁶ c) 3.6 x10⁻⁶  d) none 

10) power = _____

a) work x time b) time x work c) time/work d) work/time 

11) SI unit of power is ____

a) watt hour  b) kilowatt  c) watt d) joule hour 

12) 1000 watt=____ MW

a) 10⁶ b) 10⁹ c) 10⁻¹² d) 10⁻³

13) 1 kW= ___

a) 1000W b) 100J/100 sec c) 1000J/1000 sec d) 10⁻³ W

14) Force= Power x ____

a) velocity  b) (velocity)² c) 1/velocity d) √velocity

15) Gravitational potential energy =____

a) mgh b) mv²/2 c) 2mgh d) none

16) kinetic energy of a body is independent of ___

a) force applied b) time for which force is applied  c) elasticity of the body d) none

17) When a body travels in a circular path and covers a distance equal to 1/4th of its circymference can we conclude that work done is zero?

a) yes b) no c) both a and b d) none

18) When a body travels a circular path such that its placement is maximum equal to the diameter of the circle can we conclude work done is zero.

a) yes b) no c) data insufficient d) none 

19) power rating of a pymp=

a) power output x power input

b) power input /power output 

c) power output/ time

d) power output/ power input 

20) Power rating of a rotary pump is____

a) mv²/2 b) work output x time  c) work input x time d) work output /work input 

21) energy is____

a) the capacity to use Power

b) capacity to produce Power 

c) capacity to work 

d) capacity to do work per unit time 

22) the two basic forms of mechanical energy are :

a) PE and KE b) sound and light c) heat and tidle d) solar and wind

23) In an oscillating pendulum, KE is____ at extremes .

a) zero  b) negative c) positive d) none

24) In an oscillating pendulum the___ energy is maximum at extremes .

a) potential b) vibrational c) gravitational potential d) kinetic 

25) For a freely falling body the potential energy of the top____

a) is zero b) is completely converted to KE

c) is equal to gravitational potential energy 

d) is minimum 

26) During freefall the total energy at 3/4th the height is____

a) constant b) zero c) gravitational potential energy at the top d) 3/4th the initial potential energy 

27) In a washing machine the electrical energy is converted into____

a) sound energy b) vibration energy c) kinetic energy d) mechanical Kinetic rotational energy

28) In the case of catapult ____energy gets converter into kinetic energy.

a) muscular b) stretchable c) elastic potential  d) elastic 

29) In a photovoltaic cell _____energy converts to ___energy

a) heat, chemical  b) light, electrical c) light, wind d) thermal, kinetic 

30) Charging of a lead accomulator ______energy gets converted unto chemical energy.

a) sound  b) light heat d) electrical

31) If 1kWh o___MJ then 8MJ o____ kWh.

a) 36,72 b) 3.6,2.22 c) 0.36,222 d) none

32) 500 litres of water is____ kg

a) 5kg b) 50kg c) 500 kg d) none 

33) For a given mass of a body if velocity is doubled the kinetic energy is____

a) halved b) four times  c) 1/4 th d) none

34) For a given mass and velocity the kinetic energy remains constant if___

a) mass is 4 times and velocity is 1/2

b) mass is 1/2 and velocity is doubled

c) mass and velocity both are squared  d) none 

35) If a body of mass 5 kg is lifted from the ground level to a height of 5m then the ratio of its inertia is ____

a) 1:1 b) same c) constant d) not definer

36) During energy transformation some form of energy is given out without it being used anywhere, such energy is called____

a) backup energy  b) stored energy c) wasteful energy d) dissipated form of energy 

37) When a substance melt____

a) no energy

b) energy change takes place but is totally dissipated 

c) PE changes into KE d) none 

38) When camphor sublimes____

a) chemical energy changes into heat energy

b) PE gets converted into KE

c) it simply Converts into a gaseous state without attaining the liquid state 

d) Entire energy is lost to the surroundings 

39) A person drives a Lamborghini and reaches Delhi while another person travels the same on a bullock cart. Is the work done the same?

a) yes b) no c) data insufficient d) work done is zero 

40) A boy using a lift to reach 26 floors and a girl climbing the stairs to reach the 26th floor does the same work. Comment whether true or false ?

a) yes  b) data incomplete  c) no  d) boy spends more energy than girl 

1d 2b 3a 4b 5b 6b 7a 8c 9b 10d 11c 12d 13a 14c 15a 16d 17c 18c 19d 20d 21c 22a 23a 24c 25c 26a 27d 28d 29b 30d 31d 32c 33b 34a 35a 36d 37c 38c 39c 40b

VERY SHORT ANSWER TYPE QUESTIONS 

1) What is the condition for work to be positive ?

2) State the two conditions when the work done will be zero.

3) What should be the angle between the direction of force and direction of displacement if

a) work done is zero 

b) work done is negative

4)  What is the work done by a planet revolving around the sun ?

5) What will be the amount of work done when a boy of mass m

a) climbs to a height h through staircase

b) reaches height h through an elevator ?

6) Answer the following :

a) Name the physical quantity measured in terms of horse power.

b) 1 kWh= ____ J

7) Name the two forms of mechanical energy.

8) What is the kind of energy possessed by a moving car ?

9) What is the kind of energy possessed by a streched rubber band ?

10) State the energy possessed in the following cases:

a) a rolling football 

b) water stored in a tank at a height.

c) winding of a wrist watch

d) A stretch bow

e) water flowing over a turbine 

f) The bob of an oscillating simple pendulum at its means position.

11) State the two factors that determine the kinetic energy of a body.

12) State the three factors that determine the potential energy of a body.

13) Name the form of energy that a body may possess even when it is not in motion ?

14) An apple on a tree falls freely reaches the ground. State the kind of energy it will possess 

a) on reaching the ground 

b) in air, while falling 

c) On top of the tree 

15) State the energy changes in the following while in use:

a) burning of a candle 

b) a microphone 

c) A steam engine 

d) An electric heater 

e) A solar cell 

f) burning of wood 

g) A fire cracker.

h) An electromagnet

i) A television 

j) An electric bulb 

1) The displacement of the body should be in the direction of force.

2) a) when there is no displacement 

b) when the displacement is normal to the direction of applied

3) 90° b)  180°

4) zero 

5) a) mgh b) mgh

6) b) 3.6 x10⁶

7) kinetic energy and potential energy 

8) translation Al kinetic energy

9) elastic potential energy 

10) a) K b) p c) p d) p e) k f) k

11) mass and velocity 

12) mass, acceleration due to gravity and height

13) potential energy 

14) a) kinetic energy  b) kinetic energy + potential energy c) potential energy 

15) chemical to light and heat 

b) sound to electrical 

c) heat to mechanical

d) Electrical to heat 

e) solar to electrical 

f) chemical to heat

g) chemical to heat + sound + light 

h) electrical to magnetic 

i) electrical to light+ sound 

j) electrical to light+ heat 

NUMERICAL PROBLEMS 

1) Calculate the force applied on the body when 150 J of work is in displacing it through a distance of 10m in the direction of force ?

2) a block of ice weighing 20N slides over a frozen pond due to force of 12N applied across it. On removal of the force, the ice block continues to slide for 17m. Calculate the work done by the applied force.

3) A ball of mass 5kg is tied at the end of a string and whirled at a constant speed of 1 ms⁻¹ in a circular path of radius 5m. Calculate the work done by the centripetal force in 1 revolution.

4) a work of 4900J is performed by a porter when a load mass 50 kg is lifted to a certain height above the ground. Calculate the height through which the load is lifted .

5) a force of 5N acting on a body at a angle of 60° with the horizontal direction displaces it through a distance of 6m. Calculate the work done.

6) a body when acted upon by a force of 100 N gets displaced by 2 m. Calculate the work done by the force when displacement is

a) in the direction of force 

b) at an angle of 60° with the force 

c) perpendicular to the force

7) An athlete weighing 60 kg runs up a staircase of 10 steps each of height 1 m in 30s. Calculate the

a) force acting on the athlete

b) power spent by athlete (g= 10ms⁻² )

8) a girls mass 50 kg runs up a hall covering a distance of 10 m in 20s. Calculate the power spent by the girl. (g= 10 ms⁻²)

9) if the power of a machine is 50 kWh, at what speed can it raise a load of 50000N?

10) convert the following 

a) 7Wh in to joule 

b) 10 J into calorie 

c) 2,5 eV into joule 

11) A man of mass 50 kg climbs to the top of a building that is 40 m high. What is the gravitational potential energy attained by the man ? (g= 10ms⁻²) 

12) a car of mass 10 tons pocessing kinetic energy of 40 kJ runs down a slope of 5m. What would be the velocity of the car on reaching the ground ?

13) A ball of mass 200 g falls from a height of 5m. What will be its kinetic energy when it just reaches the ground?

14) A force is applied on a body of mass 20 kg moving with a velocity of 40 ms⁻¹. The body attains a velocity of 50 ms⁻¹ in 2s. Calculate the work done on the body.

15) A girl of mass 35 kg climbs up from the first floor of a building at a height of 4m above the ground to the third floor at a height of 12 m above the ground.

 What will be the increase in her gravitational potential energy ?

16) A ball of mass 0.2 kg falls from a height of 10m to a height of 6m above the ground. Find the ball in potential energy taken place in the hall ?

17) When a large box is taken height of 8m, the energy spent is 6.4 kJ. Calculate the mass of the box ?

18) a car and a boss are running at a same speed. If the mass of the bus is five times the mass of the car, what is the ratio of kinetic energy of bus to car?

19) Two bodies A and B with masses 4 kg and 16 kg, respectively, have the same kinetic energy. Calculate the ratio of velocity of ao to B.

20) a water reservoir on top of a tower 100m high contains water must 200 kg. Calculate the potential energy stored in the water.

21) Calculate the work done in stopping a truck of mass 5000 kg moving with a velocity of 90 km h⁻¹.

22) A hammer of mass 1 kg falls freely from a height of 2m. Calculate 

a) the velocity with which it hits the ground 

b) the kinetic energy of the hammer just before it touches ground.

23) A bullet of mass 20g moving with a velocity of 20ms⁻¹ is brought to rest by a wooden plank. Calculate the work done on the bullet before it comes to rest.

24) Calculate the kinetic energy of a body mass 0.2 kg and Momentum 45 kg ms⁻¹.

25) Calculate the work done on a ball of mass 20g to give it a moment of 10 kgms⁻¹?

26) A ball of mass 5g falls from a height of 10m. It rebounds from the ground to 8m. Find 

a) the initial potential energy of the ball.

b) the kinetic energy of the ball just before striking the ground.

c) the kinetic energy of the ball after striking the ground 

d) the loss in kinetic energy on striking the ground

27) The bob of a simple pendulum is imparted a velocity of 4ms⁻¹ at its mean position. Calculate the maximum vertical height reached by the pendulum in its extreme position

a) if there is no loss of energy due to air friction 

b) if there is 50% loss of energy due to air friction.

28) In a hydrochloric power station, 2000 kg of water is dropped through a height of 100 m in 2 second. if conversion of stored gravitational potential energy to electrical energy 60%, calculate the power output.

1) 15N 2) 204J 3) zero 4) 10m 5) 15J 6) a) 200J b) 100J c) zero 7) a) 600N b) 200 W 8) 250 W 9) 1 ms⁻¹ 10) a) 2.52 x 10⁴ b) 2.4 cal c) 4 x 10⁻¹⁹ J 11) 20000 J 12) 2.83 ms⁻¹ 13) 10J 14) 9000 J 15) 2800 j 16) 8j 17) 80 kg 18) 5:1 19) 2:1 20) 200000 j 21) 1.56 MJ 22) a) 6.32 ms⁻¹ b) 20 j 23) 4J 24) 1562.5 kJ 25) 2500 J 26) a) 0.5 j b) 0.5 j c) 0.4 j d) 0.1 j

27) a) 0.8m b) 0.4m 28) 6 x 10⁴ W

WORK, POWER AND ENERGY - TEST

 Time: 30 minutes Marks: 20

         Section 1

(All questions are compulsory)

1) a) A stone is thrown upwards. Its velocity keeps decreasing. What happens to its kinetic energy as its velocity becomes zero ? (2)

b) Piyush exerts a force of 150N in pulling a cart at a constant speed of 10 ms⁻¹.

Calculate the power exerted in pulling the cart. (2)

c) State the law of conservation of mechanical energy. (2)

d) Define 1 watt power. (2)

e) What power weighing 400N processes 500 J of kinetic energy. Calculate the velocity with which car is moving. (g= 10ms⁻¹). (2)

Section 2

(Attempt any one question out of two)

2) a) Obtain the correlation between the CGS and SI unit of the work ? (3)

b) Show by means of a diagram the energy changes taking place in an oscillating pendulum. (3)

c) State the energy transformation taking place in the following:

i) photovoltaic cell.

ii) electromagnet.

iii) electric motor

iv) burning of candle. (4)

3a) A boy weighing 40kgf climbs 30 stairs each of 30cm high in 4 minutes, while a girl weighing 30kgf does the same in 30 minutes. Compare :

i) the work done by the both

ii) the power developed by both. (3)

b) Differentiate between work done and power exerted by an object. (4)

c) Two bodies of unequal masses have the same Kinetic energies. Compare their momenta. (3)

PAPER -1

1) What is the relationship between Mechanical advantage and the velocity ratio for-

i) An ideal machine

ii) A practical machine ?

2) Which physical quantities do the following unit represent ?

a) Dioptre

b) Kelvin 

3)i) The weight of two bodies are 2.0N and 2.0 kgf respectively.

What is the mass of each body ? (g= 10 ms⁻²).

ii) If the power of a motor is 40 kw, at what speed can it raise a load of 20000 N ?

4) State the law of floatation.

5) A cube of ice whose side is 4.0cm is allowed to melt. The volume of the water formed is found to 58.24cm³. Find the density of ice.

5)  Does land cool at a slower or faster rate than water ? Give one reason for your answer.

6) Explain , why steam pipes warm a building more effectively then hot water pipes in cold countries ?

7) A ray of light , after refractions through a concave lens, emerges parallel to the principal axis. Draw a ray diagram to show the incident ray and its corresponding emergent ray.

8) The velocity of light in diamond is 121000 km/s. What is its refractive index ? (velocity of light in air is ³x 10⁸ m/s).

9) What is the voltage of electricity that is generally and supplied to a house ?

10) The neck and bottom of a bottle have a diameter 2cm and 8cm respectively. The bottle is completely filled with kerosene. If the cork in the neck is pressed with a force of 10N, what force is exerted on the bottom of the bottle ?

 Name the law/principle you have used to find this force.

11) The ratio of the amplitudes of two waves is 4:9. What is the ratio of their intensities?

12) A pendulum has a frequency of 5 vibration per second. An observer starts the pendulum and fires a gun simultaneously. He hears the echo from a cliff after 8 vibrations of the pendulum. if the velocity of sound in air is 340 m/s, what is the distance between the cliff and the observer ?

13) Which of the two wires of similar dimension, copper or nichrome, would you use for the electric heater element ? Give reasons to justify your answer.

14) Two fuse wires of the same length are rated 5A and 20A. Which of the two fuses wires is thicker and why?

15) A flag is made up of three strips of cloth of yellow, white and cyan colours. Name the colour of a particular light in which this flag will appear to be of a single colour.

16) Explain, why radium paint, consisting of zinc sulphide and a trace of radian salt, glows inthe dark.

17) An electric kettle is rated 2.5kw, 250V. Find the cost of running the kettle for 2 hours at 60 paise per unit.

18) A mass of lead is embedded in a block of aluminium(2 mm thick ). Radiation from radioactive source incident of the side of the block produce a shadow on a fluorescent screen placed beyond the block. The shadow of the block of aluminium is fainter than the shadow of lead. Give the reason for this difference.

19) A jeweller claims that he makes ornaments of pure gold that has a relative density of 19.3. He sells a angle weighing 25.25 g to a person. The clever customer weighs the bangle when immersed in water and finds that it weights 23.07g in water. With the help of suitable calculations , find out if the ornament is made of pure gold or not.

20) Draw a labelled sketch of an acid battery hydrometer and explain how it indicates whether a car battery needs recharging.

21) Give two reasons why the efficiency of a single movable pulley system is not 100%.

22) A mono-chromatic point source of light 'O' is seen through a rectangular glass block ABCD, Paths of two rays, in and outside the block, are shown in the figure below .

i) Does the source 'O' appear to be nearer or farther with respect to the surface AB?

ii) How does the shift depend on the thickness (AD or BC) of the block ?

iii) justify your answer in (ii) with the help of appropriate ray diagram.

iv) For the same rectangular glass block, which colour from the visible spectra will produce the maximum shift?

23) A postage stamp appear raised by 7.0 mm when placed under a rectangular glass block of refractive index 1.5. Find the thickness of the glass block.

24) State three characteristics of the image of an extended source, formed by a concave lens.

25) a) If a mono-chromatic beam of light, undergoes minimum deviation through an equiangular prism, how does the beam pass through the prism, with respect to its base?

b) If white light is used in the same way as in (a) above, what change is expected in the emergent beam ?

26) Sound made in front of a tall building 18m away, is repeated. Name the phenomen and briefly explain it.

27) A turning fork, held over an air column of a given length,  produces a distinct audible sound. What do you call this phenomenon? How does it occur ?

28) In a laboratory experiment for finding specific latent heat of ice, 100 gram of water at 30°C was taken in a calorimetre made of copper and of mas 10 gram of ice at 0°C was added to the mixture and kept within the liquid till the ice melted completely, the final temperature of the mixture was found to be 20°C.

a) What is the total quantity of water in the calorimetre at 20°C?

b) Specific heat capacities of water and copper being 4.2 J/g°C and 0.4 J/g°C respectively, what quantity of heat would each release in cooling down to 20°C from the initial stage ?

c) Write an expression for the heat gained by ice on melting.

d) Calculate the value of the latent heat of fusion of ice from the data discussed above.

29) Electrical power P is given by the expression:

P= (Q x V)/time

a) what do you symbols Q and V represent ?

b) Express 'power' in terms of current and resistance explaining the symbols used therein .

30) with reference to the diagram alongside , calculate 

a) The equivalent resistance between P and Q.

b) The reading of the ammeter.

c) The electrical power between P and Q.

31) The diagram shows a coil connected to a centre zero galvanometer G. The galvanometer shows, a deflection to the right when N-pole of a powerful magnet is moved to the right as shown:

a) Explain, why the deflection occurs in the galvanometer ?

b) Does the direction of the current in the coil appear clockwise or anticlockwise when viewed from the end A ?

c) State the observation in G when, both the coil and the magnet, are moved to the right at the same speed.

32) State 2 factors on which the rate of emission of thermions depends.

33) The isotopes of ²³⁸₉₂U decays by Alpha emmission to an isotope of Thorium(Th). The thorium isotope decays by beta emmission to an isotope of Protactaminum (Pa). Write down the equation to represent these two nuclear changes .

CURRENT ELECTRICITY 

1) Which among the following materials is not a very good conductor of electricity ?

a) copper b) silver c) platinum d) iron

2) Which of these substances acts as a non-ohmic resistors ?

a) nichrome wire 

b) tungaten filament 

c) copper wire 

d) aluminium filament 

3) if the resistance of a copper wire of certain length is R, then on doubling the length, its resistance :

a) will get doubled 

b) will become halved

c) will become quadrupled 

d) will become 1/4 th

4) The resistance offered by a conductor is directly proportion to its:

a) length

b) area of cross section 

c) both a and b

d) neither a nor b

5) With increase in temperature, the resistivity of manganin :

a) increases 

b) decreases 

c) remains unchanged 

d) any of these

6) Two unequal resistances are connected in parallel across a cell. Which of the following statements is true ?

a) current flowing through a smaller resistance is higher.

b) current flowing through larger resistance is higher.

c) current flowing through both the resistances is equal.

d) current can be higher in any resistance depending on the EMF of the cell.

7) In a series combination of resistors :

a) the equivalent resistance is reduced

b) the potential difference across each register is same

c) the current across each resistor is same 

d) both b and c 

8) The equivalent resistance of three resistors , each of 3 Ω resistance, when joined in parallel combination is:

a) 1Ω b) 3Ω c) 6Ω d) 9 Ω

9) Current is the rate of flow of _____per unit time.

a) charge b) free electrons c) total electrons d) both a and b 

10) The SI unit of current is _____

a) ampere b) volt c) kiloampere d) none of these 

11) 1mA is equal to ____ampere

a) 10 ampere

b) 10⁻³ ampere 

c) 10⁻⁶ ampere 

d) 10³ ampere 

12) Resistance is the opposition of flow of _____through a conductor.

a) free charges 

b) protons

c) ions 

d) none of these 

13) SI unit of resistance is____

a) ohm meter b) mho c) Ohm d) siemen

14) Ohm's law is the relationship between_____ and_____

a) pressure, volume

b) volume, temperature 

c) voltage, current 

d) resistance, current 

15) Ohm's law,____ is directly proportional to____ keeping____ constant.

a) voltage, current, temperature 

b) current, potential difference, temperature

c) temperature, voltage ,current 

d) pressure, volume, temperature 

16) ohmic conductors are conductors which ____Ohm's law.

a) accept b) disobey c) neglect d) obey 

17) Slope of voltage v/s current plot gives_____.

a) resistance b) conductance c) conductivity d) resistivity

18) slope of voltage v/s current graph is variable in___

a) conductors 

b) Ohmic resistor 

c) super conductor 

d) non-ohmic conductors 

19) Super conductors are ____

a) substance with infinity resistance 

b) substances with zero resistance

c) substances with the large conductance 

d) substances with zero conductance

20) The slope of voltage v/s current graph_____ in series circuit.

a) decreases 

b) increases

c) remains constant 

d) varies 

21) The slop of current v/s voltage graph_____ in parallel circuit.

a) increases 

b) decreases

c) is constant 

d) cannot predict

22) For a given material of wire if length is doubled its area of cross section____

a) increases

b) decreases 

c) 1/4th the original area

d) halved the original length

23) Specific resistance is _____to the length of conductor.

a) independent 

b) dependent

c) directly proportional 

d) inversely proportional 

24) Electrical energy consumed by an appliance is measured in___

a) kilowatt sec

b) kilowatt sec meter 

c) kilowatt hour 

d) watt hour 

25) Electrical energy is ____

a) Power in kW, Time in hour 

b) Power in kilovolt, Time in hour 

c) Power in kilovolt ampere, Time in hour 

d) both a and c 

26) In series combination_____ is constant.

a) potential difference 

b) current 

c) internal resistance 

d) total resistance

27) In parallel combination____ is split up.

a) current b) potential difference c) temperature d) pressure 

28) For battery conductivity ____combination of resistance is preferred.

a) series 

b) complicated 

c) parallel 

d) unique 

29) one watt-hour is equals to :

a) 36J b) 360 J c) 3600 J d) 36000 J

30) An electric bulb is rated 100W, 220V. The resistance of the filament of the bulb when it is glowing is:

a) 2.2Ω b) 0.45Ω c) 45.45 Ω d) 484 Ω

31) 1 megawatt is equals to :

a) 10⁻³W b) 10³W c) 10⁻⁶W d) 10⁶ W

32) Which of the following expression is incorrect for electrical energy ?

a) QV b) VI c) I²Rt d) V²t/R

33) The rating of a fan is 80W, 250V. The current flowing through it is :

a) 0.32A b) 3.12A c) 25.6 A d) none

REFRACTION OF LIGHT AT PLANE SURFACES 

1) Refraction of light is the phenomena of:

a) movement of light

b) bending of light

c) distribution of light

d) scattering of light

2) Light, when travels from one optical medium to another, refracts because of____

a) difference in refractive index 

b) difference in velocities

c) difference in wavelengths

d) all of the above 

3) A Ray of light bends____from the normal when it travels from an optically rarer medium to an optical denser medium.

a) away 

b) towards

c) far away 

d) very close 

4) A ray of light when travels from an optically____medium to the optically____ medium, bends away from the normal.

a) rarer, rarer 

b) denser, denser

c) rarer, denser 

d) denser, rarer 

5) A ray of light travels undeviated on passing through the optical boundary.

a) if both mediums at the same

b) if both mediums have the same referactive index 

c) the ray makes an angle of 0° with the normal

d) All the above 

6) A ray travelling parallel to the optical boundary along its surface will:

a) undergo no refraction.

b) partially refract and partiality travel undeviated 

c) suffer total internal reflection

d) none of these 

7) Two light rays incident parallel to each other on an optical boundary will undergo the same refraction.

a) true 

b) false 

c) data insufficient d) none of these 

8) Can two refracted rays be parallel to each other even if incident rays are not 

a) yes  b) no c) data insufficient  d) none of these 

9) Is Snell's law applicable when a ray of light is incident normal to the optical boundary ?

a) no b) yes c) data insufficient d) none of these 

10) Is Snell's law applicable when a ray of light is incident perpendicular to the normal at the point of incidence ?

a) yes b) no c) insufficient data

d) it is an exception for the validity of the law.

11) Lateral displacement is:

a) perpendicular shift between emergent ray and incident ray.

b) perpendicular shift between incident ray and emergent ray 

c) parallel shift between incident ray and emergent ray 

d) parallel shift between emergent ray and incident ray 

12) Lateral displacement occurs in case of :

a) cuboidal glass block

b) rectangular glass block

c) two equiangular prisms held near each other with faces parallel to one another.

d) all of the above 

13) Angular deviation in case of lateral displacement is:

a) 0° b) 90° c) 360°  d) both a and c 

14) Lateral displacement _____with increase in angle of incidence .

a) increaser 

b) decreases 

c) remains same 

d) keep changing

15) Lateral displacement decreases____ in wavelength .

a) decrease 

b) increase 

c) no change 

d) none of the above 

16) Greater the optical density, ____ is the the lateral displacement.

a) greater 

b) less

c) equal 

d) none of these 

17) Slimmer the glass slab _____ is the lateral displacement.

a) greater 

b) less

c) equal 

d) none of these 

18) A ray of light from the lighthouse reaches the submarine which is underwater. The sailor places a plane mirror such that the angle between the light ray and the mirror is 0°. Where would he see the lighthouse ?

a) he won't see the light source at all 

b) at the same position as a no refraction occurs 

c) at the same position as light reverses along with the same path.

d) it is pitch dark to relocate the light from the submarine.

19) A fish while on the surface of the water has its angle of view as α, while it is in water the angle of vision becomes β. Compare the two angles of view.

a) α = β b) α > β c) α < β d) can't say

20) A fisherman points toward the____ while harpoon hunting.

a) tail b) eye c) head d) body 

21) A coconut tree appears to be___ when viewed by a sea diver from  below the water surface.

a) taller 

b) shorter 

c) same size 

d) distorted 

22) Starts appear to Twinkle while planets do not because:

a) they are luminous as compared to planets.

b) they are at far off distances.

c) stars undergo T.I.R while planets refract.

d) both a and b 

23) A pond appears shallow than its actual depth because of:

a) reflection 

b) dispersion 

) scattering

d) refraction

24) Face of a person sitting near a camp fire appears to shimmer because of:

a) total internal reflection 

b) refraction of light 

c) scattering of light 

d) dispersion of light 

25) Critical angle is the angle of_____

a) refraction

b) incidence 

c) reflection 

d) emergence

26) The refractive index is related to critical angle as____

a) reciprocal of angle of incidence 

b) reciprocal of angle of emergence

c) (critical angle)²

d) [sin C]⁻¹

27) Velocity of light is more in ____than_____

a)  air, water

b) water, air

c) sea water, mineral water 

d) brown glass, transparent glass

28) Velocity of light is____ to refractive index.

a) directly proportional 

b) inversely proportional

c) independent 

d) none of the above

29) Greater the refractive index, ____the apparent depth.

a) more b) same c) less d) none of these 

30) Thicker the glass slab, ____is the object appearing to be raised 

a) more b) less c) uniform d) all of these 

31) Greater the angle of refraction, ____ the lateral displacement

a) same b) uniform c) less d) proportionate 

32) Diamond sparkles only in the dark. Is this statement true ?

a) yes 

b) Incomplete data 

c) no d) none of these 

33) if light is not incident on diamond, The diamond would never sparkle.

a) true 

b) false 

c) data insufficient 

d) none of these 

34) Diamonds sparkles because of ____

a) T.I.R followed by entrapping of light inside it

b) refraction followed by T.I.R

c) T.I.R. followed by refraction

d) none of these 

35) Water being completely transparent can appear shiny like a mirror due to:

a) total internal reflection

b) dispersion 

c) refraction of light

d) absorption of light

36) A lightning strikes a window pane and produces a crack in it. This crack appears silvery because of___

a) total internal refraction

b) Fineness of the crack

c) light being entrapped in the crack

d) Diffraction 

37) Formation of mirage is because of the thirst felt by the Nomadic traveller ?

a) true  b) false c) incomplete data d) none 

38) Mirage is a consequence of T.I.R. followed by successive refraction.

a) yes b) no c) data insufficient d) none of these 

39) High speed internet is provided by the use of____

a)  jio networks  b) 5G plan 

c) Airtel network d) Optical fiber

40) Optical fibre works on the principle of____

a) satellite signals 

b) total internal reflection 

c) optical transmission 

d) internet mobile towers 

41) Can a black body which absorbs 100% light appears to be sulvery ?

a) yes b) no  c) data insufficient d) none 

42) Is black a colour of light 

a) yes b) no c) data insufficient d) none

43) An equiangular prism is a

a) total reflecting prism 

b) refracting prism 

c) dispersing prism 

d) all of these 

44) The deviation produced in case of an equiangular prism is called ____

a) equal deviation 

b) angular deviation

c) lateral deviation 

d) none of these 

45) The measure of angular deviation in case of a prism is called____

a) referangibility of light 

b) refractibility of light 

c) reflective of light

d) reversibility of light 

46) For minimum deviation, the angle of incidence is___ angle of refraction.

a) less than b) greater than 

c) equal to  d) directly proportional to 

47) The emergent Ray and incident rays should be equally all inclined to the refracting surfaces of a prism in____

a) no deviation condition 

b) minimum deviation condition 

c) maximum deviation position 

d) equal deviation position 

48) the refracted ray is____ to the base of the prism is minimum deviation position.

a) parallel b) perpendicular c) collinear d) inclined 

49) is it correct to say that angle of incidence is equal to angle of emergence ?

a) yes b) no c) both a and b d) none 

50) is angular deviation minimum applicable for isosceles right-angled prism ?

a) yes b) no c) not defined d) none of these 

REFRACTION OF LIGHT AT PLANE SURFACES

1) Angle of incidence is equal to the angle of___for a rectangular glass slab.   

2) That angle of incidence for which corresponding angle of refraction is 90°.   

3) A Ray of light bonds____ while travelling from optically denser medium to rarer .  

4) Refracted ray us parallel to the base while in____ position.   

5) Refraction occurs because of difference in ____densities.    

6) The ray of light reflects back in the same medium suffering total___ reflection.    

7) Optical illusion seen in deserts during hot and dry day is called___.  

8) Negative mirage seen in the sky at night is called ____.       

9) Pencil appears to be bent when dipped in water because of___ of light.   

10) The perpendicular shift in ray of light after refracting through a rectangular glass slab is called ?    

11) Refractive index is the ratio of sine of angle of incidence to sine of angle of refraction. This law is called the___ law.      

12) ____ sparkles in the dark due to its low critical angle to 24°.     Diamond 

13) An object can be rotated through 180° by using total reflecting___.     

REFRACTION OF LIGHT THROUGH A LENS 

1) Power of convex lens is_____.     

2) A converging lens is a_____ lens.      

3) Virtual image in case of a simple microscope is highly____.     

4) A ray passing through_____centre goes undeviated on refraction.    

5) A parallel ray of light would ____after refracting through a concave lens.     

6) A____ lens is a diverging lens.      

7) ____of a lens is the measure of convergence or divergence of a lens.    

8)  A ray of light on passing through any lens at any point other than optical centre___ due to refraction of light.      

9) Power of dioptre is reciprocal of focal length in____.      

10) SI unit of power of lens is____.     

11) Focal length for concave lens is____.       

12) The size of the image is____as the object when object is placed at 2C.