You can get the important Physics 1st Year Chapter 4 Work and Energy MCQs with Answers here. Work is defined as the product of Work and displacement. Work is done by two forces i.e. Constant and Variable Forces. Work is also done by the Gravitational field. Another important thing in this Chapter is power. Power is the measure of the rate at which work is done. The work-Energy principle and Escape Velocity also links with Work. Absolute Potential Energy has a relation with Energy. Conservation of Energy and Sources of Energy (Energy from tides, from waves, Solar Energy, from Biomass, from Waste products, and Geothermal Energy) are also described in the Chapter. So, get the important MCQs here and prepare for the Entry Test.

## Physics 1st Year Chapter 4 Work and Energy MCQs

### KEY POINTS

- Work done by Constant and Variable Forces
- Work is done by Gravitational Field
- Power/Power and Velocity
- Work-Energy Principle
- Absolute Potential Energy
- Escape Velocity
- Interconversion of P.E and K.E
- Conservation of Energy
- Non-Conservational Energy Sources

**Question#1. Work done will be maximum if the angle between the force F and displacement d is?**

- 45°
- 90°
- 180°
- 0°

### Answer

### Answer

**0°**

**Question#2. A field in which the work is done in moving a body in a closed path is zero is called?**

- Electric field
- Conservative field
- Electromagnetic field
- Gravitational field

### Answer

### Answer

**Conservative field**

**Question#3. When a force is perpendicular to the direction of motion of the body, then work done on the body is?**

- Zero
- Minimum
- Infinity
- Maximum

### Answer

### Answer

**Zero**

**Question#4. Which of the following types of force does not work on the particle when it acts on it?**

- Frictional force
- Gravitational force
- Elastic force
- Centripetal force

### Answer

### Answer

**Centripetal force**

**Question#5. If a body a mass of 2 kg is raised vertically through 2m, then the work done will be?**

- 38.2 J
- 392.1 J
- 39.2 J
- 3.92 J

### Answer

### Answer

**39.2 J**

**Question#6. An elevator weighing 3.5×10 ^{+10} N is raised to a height of 1000m in the absence of friction, the work done is?**

- 3.5×10
^{3}J - 3.5×10
^{4}J - 3.5×10
^{6}J - 3.5×10
^{9}J

### Answer

### Answer

**3.5×10**

^{9}J**Question#7. The average power and instantaneous power become equal if work is done?**

- Any rate
- Variable-rate
- Uniform rate
- High rate

### Answer

### Answer

**Uniform rate**

**Question#8. The relation between horsepower and watt is?**

- 1 hp = 546 watts
- 1 hp = 746 watts
- 1 hp = 1000 watts
- 1 hp = 946 watts

### Answer

### Answer

**1 hp = 746 watts**

**Question#9. Proton, electron and neutron and α particles have same momentum. Which of them have highest K.E?**

- Proton
- Electron
- Neutron
- α-particle

### Answer

### Answer

**Electron**

**Question#10. The power output of a lamp is 6W. How much energy does the lamp give out in 2 minutes?**

- 3 J
- 120 J
- 720 J
- 430 J

### Answer

### Answer

**720 J**

**Question#11. Work done by a variable force is determined by dividing?**

- Force into the small interval
- Displacement into the small interval
- Both force and displacement into small intervals
- Force into small and displacement into large intervals

### Answer

### Answer

**Displacement into small interval**

**Question#12. Work done on the body equals?**

- Change in its K.E always
- Change in its P.E always
- Change in its K.E or change in its P.E
- Neither change in K.E nor change in its P.E

### Answer

### Answer

**Change in its K.E or change in its P.E**

**Question#13. The escape velocity of a body in the gravitational field of Earth is independent of?**

- it’s mass
- the angle at which it is thrown
- both its mass and the angle at which it is thrown
- the gravitational field of Earth

### Answer

### Answer

**both its mass and the angle at which it is thrown**

**Question#14. The tides raise the water in the sea roughly in a day?**

- Once
- Twice

- Four-time
- Eight-time

### Answer

### Answer

**Twice**

**Question#15. The source of geothermal energy is: **

- The decay of radioactive elements in the earth
- Compression of material in the earth
- The residual heat of the earth
- All as side in a, b and c

### Answer

### Answer

**All as side in a, b and c**

**Question#16. The highest value of escape velocity in the solar system is for the planet?**

- Earth
- Neptune
- Jupiter
- Moon

### Answer

### Answer

**Jupiter**

**Question#17. Work done by the force of friction is?**

- Always positive
- Always negative
- Positive only for the small frictional force
- Positive only for the large frictional force

### Answer

### Answer

**Always negative**

**Question#18. Gravitational P.E of a body can be found by?**

- no formula
- mg.h
- – Gm/r
- Both b and c

### Answer

### Answer

**mg.h**

**Question#19. If velocity is doubled, then?**

- Momentum increase to 4 times and K.E increases to 2 times
- Momentum and K.E remain the same
- Momentum increases to 2 times and K.E increases constant
- Momentum increases to 2 times and K.E increases to 4 times

### Answer

### Answer

**Momentum increases to 2 times and K.E increases to 4 times**

**Question#20. We get energy from food during a day which is equivalent to the energy obtained from _______ liter petrol?**

- 1
- ½
- 1/3
- ¼

### Answer

### Answer

**1/3**

**Question#21. One megawatt-hour is equal to?**

- 3.6×10
^{6 }J - 3.6×10
^{12}J - 3.6×10
^{9}J - 3.6×10
^{8}J

### Answer

### Answer

**3.6×10**

^{8}J**Question#22. Which of the following is not a conservative force?**

- Friction
- Electric
- Gravitational
- Elastic spring force

### Answer

### Answer

**Friction**

**Question#23. Does work have the dimension as that of the same as that of?**

- Torque

- Angular momentum
- Linear momentum
- Power

### Answer

### Answer

**Torque**

**Question#24. The pull of the Moon can distort the continents by pulling and up and down by as much as?**

- 25mm
- 25cm

- 250cm
- 2.5cm

### Answer

### Answer

**25cm**

**Question#25. The relation between the escape velocity V _{esc} and orbital speed V_{o} is given by?**

- V
_{esc}= 1/2V_{o} - V
_{esc}= √2 V_{o} - V
_{esc}= V_{o} - V
_{esc}= 2V_{o}

### Answer

### Answer

**V**

_{esc}= √2 V_{o}**Question#26. The escape velocity from the earth’s surface in km s ^{-1} is about?**

- 4.2 km s
^{-1} - 7.5 km s
^{-1} - 9.5 km s
^{-1} - 11 km s
^{-1}

### Answer

### Answer

**11 km s**

^{-1}**Question#27. If the Moon radius is 1600 km and g on its surface is 1.6 ms ^{-2}, then the escape velocity on the moon is?**

- 1600ms
^{-1} - 50.6ms
^{-1} - 71.6ms
^{-1} - 2400ms
^{-1}

### Answer

### Answer

**2400ms**

^{-1}**Question#28. When two protons are brought close, their?**

- Kinetic energy increases
- P.E. increases
- P.E. decreases
- P.E. does not change

### Answer

### Answer

**P.E. increases**

**Question#29. When an arrow is released from its bow, its energy is transformed from?**

- The heat energy to K.E
- Elastic P.E to K.E
- Chemical energy to elastic P.E
- K.E to elastic P.E

### Answer

### Answer

**Elastic P.E to K.E**

**Question#30. Two bodies of 4g and 16g have the same K.E. What is the ratio of their momentum?**

- 2:1
- 4:1
- 1:2
- 1:4

### Answer

### Answer

**1:2**

**Question#31. Escape velocity depends upon the radius of Earth. Which one shows its proper dependence?**

- V α R
- V α R
^{1/2} - V α R
^{1/3} - V α R
^{-1}

### Answer

### Answer

**V α R**

^{1/2}**Question#32. The temperature of hot igneous rocks is about?**

- 20,000 °C or more
- 2000°C or more
- 200° C or more
- 20°C or more

### Answer

### Answer

**200° C or more**

**Question#33. A tennis ball is dropped on to a horizontal surface. As the ball bounces up and down, the height of each bounce gradually decreases, during the motion of the ball?**

- The K.E of the ball is constant
- The sum of P.E and K.E energies of the ball is constant
- The P.E of the ball is constant
- The total energy of the ball, ground, and the air is constant

### Answer

### Answer

**The total energy of the ball, ground and air is constant**

**Question#34. The propulsion force of a rocket is?**

- Non-conservative force
- Conservative force
- Conservative and rocket has reached high altitude
- None of these

### Answer

### Answer

**Non-conservative force**

**Question#35. A car is driven along a level road. The total energy input from petrol is 60kJ and the car wastes 45kJ of energy, what is the efficiency of the car?**

- 25%
- 15%
- 45%
- 75%

### Answer

### Answer

**25%**

**Question#36. Geothermal energy is a __________source of energy.**

- Non-renewable
- Stable
- Renewable
- None of the above

### Answer

### Answer

**Renewable**

**Question#37. The source of tidal energy is?**

- Sun
- Earth
- Both a and b
- Moon

### Answer

### Answer

**Moon**

**Question#38. ________ cell converts solar energy into electrical energy.**

- Rotary
- Photovoltaic
- Galvanic
- None of these

### Answer

### Answer

**Photovoltaic**

**Question#39. From which source would the release of energy be affected by the change in the earth’s gravitational field?**

- Geothermal
- Chemical
- Hydroelectric

- Nuclear

### Answer

### Answer

**Hydroelectric**

**Question#40. The center of the Sun produces large amounts of energy, what is the source of this energy?**

- Chemical reaction
- Nuclear fission
- Nuclear fusion
- Radioactive decay

### Answer

### Answer

**Nuclear fusion**