### Most Important MCQ’s of Physics Part 1 (Chapter 4-6)

**2. Which of the following forces do no work in displacing an object?**

(a) Frictional force (b) Gravitational force

(c) Electric force (d) centripetal force

**3. Work done in raising a body of weight w through height h is**

(a) wh (b) 0

(c) -wh (d) wh sin?

**4. The dimensions of work are**

(a) [MLT?1] ( b) [MLT ?2]

(c) [ML2T?1] (d) [ML2T?2]

**5. Work is said to negative when the angle between force and displacement is**

(a) 90o (b) 0o

(c) 180o (d) between 90o and 180o

**6. When a vehicle is moving at constant velocity and a constant engine force is used to overcome friction, the product of force times velocity is a measure of**

(a) kinetic energy of the vehicle (b) work done by the vehicle (c) motive power of the vehicle (d) inertia of the vehicle.

**7. kWh is the unit of**

(a) power (b)energy

(c) work (d) electricity

**8. The dimensions of power are**

(a) [ML2T?1] (b) [ML2T?2]

(c) [ML2T?3] (d) [MLT?2]

**9. A lift of mass 200 kg moves upward with uniform velocity of 4 ms-1. If the efficiency of the motor is 70 %, the input power of the motor is**

(a) 11.2 kW (b) 16.7 kW

(c) 7.84 kW (d) 19.42 kW

**10. 1 hp equals**

(a) 746 J (b) 550 ft-lb

(c) 550 ft-lb s-1 (d) 550 W

**11. The dimensions of kinetic energy are**

(a) [ML2T?2] (b) [ML?2T2] (c) [ML2T?1] (d) [ ML2T?2]

**12. Two masses of 1 g and 4 g are moving with equal kinetic energies. The ratio of the magnitudes of their linear momenta is**

(a) 4 : 1 (b) 2 : 1

(c) 1 : 2 (d) 1 : 4

**13. A trolley of mass 60 kg moves on a frictionless horizontal surface and has a kinetic energy of 120 J. A mass of 20 kg is lowered vertically into the trolley. The total kinetic energy of the system is**

(a) 60 J (b) 72 J

(c) 120 J (d) 144 J

**14. A bomb of 9 kg explodes into two pieces of masses 3 kg and 6 kg. The velocity of 3 kg mass is 16 ms-1. The kinetic energy of 6 kg mass will be**

(a) 96 J (b) 192 J

(c) 384 J (d) none of these

**15. The potential energy of a 50 kg person jumping from a height of 10 m is**

(a) 49 J (b) 490 J

(c) 5000 J (d) 500 J

**16. Which one of the followings is correct?**

(a) Watt and watt-hour represent the same quantities

(b) Watt represents energy and watt-hour power

(c) Watt represents power and watt-hour energy

(d) none of these

**Most Important MCQ’s of Physics Part 1**

**17. The dimensions of elastic potential energy are**

(a) [ML2T?2] (b) [ML?2T2]

(c) [ML2T?1] (d) [ ML2T?2]

**18. If M be the mass of Earth, R its radius and G the gravitational constant, then the amount of work done on a body of mass m to escape it completely from the Earth’s field is**

GmM GmM

(a) (b)

R 2R 3GmM 2GmM

(c) (d)

2R R

**19. If g be the acceleration due to gravity on Earth’s surface, the gain in potential energy of an object of mass m raised from the surface of Earth to a height equal to the radius of the Earth is**

(a) mgR (b) mgR

(c) mgR (d) 2 mgR

**20. When two electrons come close to each other, their**

(a) KE change into electrical energy (b) KE change into PE

(c) electrical energy change into PE (d) none of these

**21. A body is projected vertically from the surface of Earth of radius R with a velocity of equal to half the escape velocity. The maximum height gained by the body is**

R R

(a) (b)

4 3

R

(c) (d) R

2

**22. The intensity of solar energy intercepted by Earth at normal incidence daily is**

(a) 1.4 kWm?2 (b) 14 kWm?2

(c) 1.0 kWm?2 (d) 0.14 kWm?2

**23. A long spring stretched by 2 cm has potential energy U. When stretched by 10 cm, its potential energy will be**

(a) 5 U (b) 2.5 U

U

(c) 25 U (d)

5

**24. The expression for the escape velocity is given by**

(a) 2gR2 (b) 2gR

gR2

(c) (d) 2gR

2

**25. An example of non-conservative force is**

(a) electric force (b) spring force

(c) frictional force (d) magnetic force

**26. Work-energy theorem can be expressed as**

(a) Fa?Kf ?Ki (b) F•v ?Kf2 ?Ki2

(c) ma?Kf2 ?Ki2 (d) Fd?Kf ?Ki

**27. 1 kWh equals**

(a) 0.36 MJ (b) 3.6 MJ

(c) 36 MJ (d) 360 MJ

**28. If the mass and speed of a body are doubled, its kinetic energy becomes**

(a) 3 times (b) 4 times

(c) 8 times (d) 16 times

**30. The absolute potential energy of a body in the gravitational**

** field of Earth is**

(a) directly proportional to the mass of the body

(b) inversely proportional to the mass of the body

(c) independent of the mass of the body

(d) none of these

**31. The average and instantaneous powers become equal when**

** work is done at**

(a) any rate (b) constant rate

(c) increasing rate (d) decreasing rate

**32. An object of mass m passes a point P with velocity v and slides up a frictionless incline to stop at point Q, height h above P. When a second object of mass m passes P with a**

** velocity of v, it will rise to**

(a) h (b) h

(c) h (d) 2h

**33. The dimensions of work are the same as that of**

(a) torque (b) momentum

(c) force (d) power

**34. The muscular power of an athlete who spends 500 J of energy**

to lift a load in 2 s is

(a) 125 W (b) 250 W

(c) 500 W (d) 1000 W

**35. The value of escape velocity on the surface of Earth is**

(a) 11.2 × 102 ms?1 (b) 11.2 × 103 ms?1

(c) 11.2 × 104 ms?1 (d) 11.2 × 105 ms?1

**36. Tidal waves are produced due to the gravitational pull of**

(a) Earth (b) Sun

(c) Moon (d) none of these

**37. The source of geothermal energy is the**

(a) rotation of Earth around the Sun

(b) fusion in Sun

(c) radioactive decay in Earth

(d) tidal energy

**38. Energy released in the process of fission and fusion is known**

** as**

(a) geothermal energy (b) magnetic energy

(c) electrical energy (d) nuclear energy

**39. Solar cells are made of a material called**

(a) silicon (b) iron

(c) carbon (d) aluminum

**40. The units of energy are the same as that of**

(a) force (b) power

(c) work (d) torque

**Key to Test Chapter 4**

1 c 21 c

2 d 22 c

3 c 23 c

4 d 24 b

5 d 25 c

6 c 26 d

7 b 27 b

8 c 28 c

9 a 29 c

10 c 30 a

11 a 31 b

12 c 32 a

13 c 33 a

14 b 34 b

15 c 35 b

16 c 36 c

17 a 37 c

18 a 38 d

19 a 39 a

20 b 40 c

Chapter 5

**1. A point mass moves along the circumference of a circle of radius R. As it completes 4 rotations, its displacement and distance covered are**

(a) 0 and 8?R (b) 8?R and 0

(c) 8?R and 2 R (d) none of these

**3. 1 rad equals**

(a) 53.7o (b) 35.7o

(c) 57.3o (d) 75.3o

**4. The dimensions of angular displacement are**

(a) [L] (b) [Lo]

(c) [L2] (d) [L??]

**10. The ratio of the angular speed of the minute hand to the hour hand of a clock is**

(a) 1 : 6 (b) 6 : 1

(c) 1 : 12 (d) 12 : 1

**12. All points of a rigid body rotating about a given axis have the same**

(a) tangential velocity (b) angular velocity

(c) tangential acceleration (d) angular acceleration

**15. A satellite circles the Earth with a speed v at a distance r from the centre of Earth. Increasing the speed twice will make the satellite move in a circle of radius**

(a) 2 r (b) r/4

(c) 4 r (d) r/2

**16. When a stone is whirled in a vertical circle by a string, the tension in the string is maximum at the**

(a) centre (b)top

(c) bottom (d) neither of these points

**17. Moment of inertia has the dimensions**

(a) [MLT] (b) [ML2T?2 ]

(c) [ML2] (d) [ML2T?1]

**18. Rotational analogue of force is**

(a) angular momentum (b) moment of inertia

(c) moment of force (d) torque

**19. The moment of inertia of a body depends upon**

(a) mass of a body and its size

(b) its angular momentum

(c) mass of a body and its angular speed

(d) mass as well as its distribution about the axis of rotation.

**20. The angular momentum L is given by**

(a) m? (b) ? × r

(c) r × F (d) r × p

**21. Rate of change of angular momentum is equal t**o

(a) force (b) impulse

(c) torque (d) inertia

**23. If Earth shrinks half of its present size, its new angular velocity of rotation about its axis of rotation becomes**

(a) twice (b) three times

(c) four times (d) six times

**26. The weight of a man in an elevator descending with an acceleration of 4.9 ms?? will become**

(a) twice (b) half

(c) zero (d) unchanged

**32. The physical quantity which produces angular acceleration in a body is called**

(a) angular velocity (b) momentum

(c) centripetal force (d) torque

**33. The rate of change of angular momentum of a body is called**

(a) applied torque (b) force

(c) impulse (d) moment of force

**34. Angular momentum of a body under the central force is**

(a) zero (b) maximum

(c) minimum (d) constant

**36. The number of geostationary satellites required for global TV transmission is**

(a) 2 (b) 3

(c) 4 (d) 6

**37. A geostationary satellite completes one revolution around the**

Earth in

(a) 6 hr (b) 12 hr

(c) 18 hr (d) 24 hr

**38. Moment of inertia of a solid sphere of mass M and radius R about an axis passing through its centre is**

(a) MR (b) MR2

(c) MR2 (d) MR2

**40. Finite angular displacement of a rotating body is taken as**

(a) vectors (b) scalars

(c) neither scalars nor vectors (d) both scalars as well as vectors

**Answers Key**

1 a 21 c

2 d 22 b

3 c 23 c

4 b 24 d

5 b 25 c

6 a 26 b

7 d 27 d

8 b 28 b

9 b 29 b

10 d 30 b

11 c 31 b

12 b 32 d

13 a 33 a

14 b 34 d

15 b 35 a

16 c 36 b

17 c 37 d

18 d 38 b

19 d 39 b

20 d 40 b

**The frictional effect present between different layers of a moving fluid is called its**- fluidity (b) density

(c) viscosity (d) none of these

**Stoke’s law holds for bodies moving through**- free space (b) horizontal plane

(c) viscous medium (d) air

**A force that opposes the motion of a body moving through**

it is called

- frictional force (b) gravitational force

(c) drag force (d) impulsive force

**The rate of flow of a liquid is expressed in the units of**- Nm
^{3}s (b) kg m^{3}s^{?}^{1}

- Nm

(c) m^{3}s^{2} (d) m^{3}s^{?}^{2}

**Stoke’s law holds for bodies when these have**- any shape (b) spherical shape

(c) oblong shape (d) rectangular shape

**The co-efficient of viscosity is expressed in the units of**- kgsm-1 (b) kgm-1s–2

(c) kgsm-2 (d) kgm-1s-1

**Most Important MCQ’s of Physics Part 1**

**The dimensions of co-efficient of viscosity are**- ML2T-1 (b) ML-2T-1

(c) MLT-1 (d) ML-1T-1

**A rain drop falls down in air with**- increasing speed and increasing acceleration
- decreasing speed and increasing acceleration
- increasing speed and decreasing acceleration
- decreasing speed and decreasing acceleration

**The terminal velocity of a body falling through a fluid**- increases with increasing mass
- decreases with increasing mass
- is independent of its mass
- is independent of its size

**The terminal velocity of a spherical droplet is**- inversely proportional to its radius
- directly proportional to its radius
- directly proportional to the square of its radius
- inversely proportional to the square of its radius

**A fog droplet falls vertically with an acceleration**- equal to g (b) less than g (c) equal to zero (d) greater than g

**Hails fall faster than rain drops due to their**- greater mass (b) greater size

(c) solid shape (d) none of these

**The liquid in a perfume sprayer emerges at high speed because of the**- work done in pressing the nozzle
- creation of the pressure difference
- narrow size of the nozzle
- smaller density of the liquid

**An aerofoil moves through the air and experiences lift. Which of the following statements is / are true?**- Air moves faster across the top of the aerofoil than across the bottom
- Air pressure below the aerofoil is greater than above 3. The upward lift is independent of the velocity of the aerofoil

- 1 only (b) 1 and 2 only

(c) 2 and 3 only (d) 2 only

**Identify the correct answer in the light of Bernoulli’s theorem**- Where the speed of the fluid is high, the pressure will be low
- Where the speed of the fluid is low, the pressure is also low
- This theorem holds for turbulent flow of the fluid
- Pressure of a fluid is independent of its speed

**For which body position, will the systolic blood pressure have the least value in the body?**- Standing up right (b) Sitting relaxed

(c) Lying horizontally (d) Standing on one’s head

**Two boats moving parallel to each other in water in the same direction**- are moved away from each other
- are pulled towards each other
- continue their motion unaffected
- none of these

**1 torr equals**- 33 Nm-2 (b) 1.333 Nm-2

(c) 133.3 Nm-2 (d) 1333 Nm-2

**Study of fluids in motion is called**- fluid resistance (b) fluid mobility

(c) fluid static (d) fluid dynamics

**Drag force is also called**- terminal force (b) retarding force

(c) increased force (d) attractive force

**Viscosity of air at 30**^{0}C in Nsm^{-2}is- 019 ? 10
^{-3}(b) 0.019 ? 10^{5}

- 019 ? 10

(c) 0.019 ? 10^{6} (d) 0.019 ? 10^{7}

**Irregular flow of a fluid is also called**- turbulent flow (b) laminar flow
- both ‘a’ and ‘b’ (d) none of these

**Blood is**- a compressible fluid (b) an incompressible fluid

(c) non-viscous fluid (d) an ideal fluid

**Carburetor of a car use**s- Newton’s laws (b) Kepler’s laws

(c) Bernoulli’s equation (d) Coulomb’s law

**Fluids that do not flow easily have**(a) large co-efficient of viscosity.- small co-efficient of viscosity.
- intermediate co-efficient of viscosity.
- no viscosity.

**Above a certain velocity, the motion of a fluid becomes**- steady and regular (b) unsteady and regular

(c) steady and irregular (d) unsteady and irregular

**Taller the chimney, ________ will be the draught.**- smaller (b) steadier

(c) slower (d) greater

**Blood vessels are**- rigid (b) non-rigid

(c) hard (d) flexible

**Sphygmomanometer is a device to measure**- pulse rate (b) red cells in blood

(c) blood pressure (d) blood speed

**The path followed by the particle of a fluid is called**- streamline path (b) line of flow

(c) orderly path (d) none of these

**In a steady flow**,- the streamlines cross line of flow
- the streamlines are perpendicular to the line of flow (c) the streamlines coincide the line of flow (d) none of these.

**An incompressible fluid is one in whic**h

- change of pressure does not change the density.
- change of pressure changes density of the liquid
- increase of pressure produces decrease of density (d) decrease of pressure produces increase of density

December 3, 2016

good info

December 5, 2016

Where are the answers of chapter 6 mcqs?

December 5, 2016

We couldn’t find them..so try to solve them ….sorry for the inconvenience.

December 5, 2016

Okay sure. And also, physics part 2. There’s only one chapter Electrostatics. It is written chapter 13, 14,15 etc but theres only one chapter 12.

December 6, 2016

Sorry for the inconvenience .We have resolved that issue.