Class 8 Science Practice Set: Energy
Review targeted practice sets for Class 8 Science Energy. Built according to official educational guidelines for the 2026-27 academic year, these downloadable worksheets support daily revision and core concept reinforcement.
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View or download the dedicated Energy practice resource below. Engaging with these objective and subjective questions daily ensures continuous academic progress and mastery of the 2026-27 curriculum.
A. Work and Energy
1. In physics, when is work said to be done? 2. The equation and unit of work. 3. The factors it depends on.
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Answer: Work is done when a force acts on an object and the object moves in the direction of the force. Work = force x displacement (W = F x s). Its SI unit is the joule (J), where 1 J = 1 N x 1 m. Work depends on the force applied and the displacement.
Teacher's Note: Use the key term in your answer.
4. A force of 20 N causes a displacement of 4 m. Find the work done.
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Answer: W = F x s = 20 x 4 = 80 J.
Teacher's Note: Give an example if the question allows.
5. A work of 4800 J is done to lift a 40 kg load. Find the height.
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Answer: W = m g h, so h = 4800 / (40 x 10) = 12 m.
Teacher's Note: Write a short, clear answer.
1. What is energy? State its unit. 2. Forms of energy.
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Answer: Energy is the ability to do work. Its SI unit is the joule. Forms: mechanical (kinetic and potential), heat, light, sound, electrical, chemical and nuclear.
Teacher's Note: Remember this for your exam.
3. Define kinetic energy, potential energy and gravitational potential energy.
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Answer: Kinetic energy is the energy of a body due to its motion. Potential energy is the energy stored in a body due to its position or condition. Gravitational potential energy is the energy a body has due to its height above the ground.
Teacher's Note: Learn this point and write it in your own words.
4. The equation for kinetic energy and its factors. 5. Three types of potential energy. 6. The equation for gravitational PE and its factors.
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Answer: KE = (1/2) m v squared; it depends on the mass and the speed. Types of PE: gravitational, elastic and electric. Gravitational PE = m g h; it depends on the mass, the height and gravity.
Teacher's Note: Use the key term in your answer.
B. Numerical Problems (g = 10 m/s2)
1. Kinetic energy of a bike of mass 1500 kg moving at 15 m/s.
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Answer: KE = 1/2 x 1500 x 15 x 15 = 168,750 J.
Teacher's Note: Give an example if the question allows.
2. Kinetic energy of a 0.03 kg bullet at 300 m/s.
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Answer: KE = 1/2 x 0.03 x 300 x 300 = 1,350 J.
Teacher's Note: Write a short, clear answer.
3. Gravitational PE of a 12.0 kg object 4.8 m high.
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Answer: PE = m g h = 12 x 10 x 4.8 = 576 J (with g = 9.8, 564.5 J).
Teacher's Note: Remember this for your exam.
4. A mango has PE 180 J and mass 0.36 kg. Find the height.
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Answer: h = PE / (m g) = 180 / (0.36 x 10) = 50 m.
Teacher's Note: Learn this point and write it in your own words.
5. A softball 2.4 m above the ground has PE 568 J. Find the mass.
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Answer: m = PE / (g h) = 568 / (10 x 2.4) = 23.7 kg (approximately).
Teacher's Note: Use the key term in your answer.
6. A 14.5 kg container, PE 435 J. Find the height.
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Answer: h = 435 / (14.5 x 10) = 3 m.
Teacher's Note: Give an example if the question allows.
7. A 1 kg chocopie has KE of 32 J. Find the speed.
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Answer: v squared = 2 x KE / m = 64, so v = 8 m/s.
Teacher's Note: Write a short, clear answer.
8. A football with KE 100 J moves at 5 m/s. Find the mass.
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Answer: m = 2 x KE / v squared = 200 / 25 = 8 kg.
Teacher's Note: Remember this for your exam.
C. Energy Transformation
1. What is the law of conservation of energy?
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Answer: Energy can neither be created nor destroyed; it only changes from one form to another. The total energy of the universe remains constant.
Teacher's Note: Learn this point and write it in your own words.
2. Energy transformation in (a) an LED (b) a ceiling fan (c) a dry cell.
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Answer: (a) An LED changes electrical energy into light energy (with a little heat). (b) A ceiling fan changes electrical energy into kinetic energy (and a little sound and heat). (c) A dry cell changes chemical energy into electrical energy.
Teacher's Note: Use the key term in your answer.
3. Differentiate between energy and power.
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Answer:
| Energy | Power |
|---|---|
| The capacity to do work | The rate of doing work |
| Unit: joule | Unit: watt (J/s) |
| Can be stored | Cannot be stored |
Teacher's Note: Give an example if the question allows.
18. Define: joule, energy, kinetic energy, potential energy, gravitational potential energy, power.
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Answer: Joule: the work done when a force of 1 N moves an object 1 m. Energy: the ability to do work. Kinetic energy: energy due to motion. Potential energy: stored energy due to position or state. Gravitational PE: energy due to height. Power: the rate of doing work.
Teacher's Note: Write a short, clear answer.
D. Exercise
(i) Work is a ____ quantity. (ii) Energy is transformed every ____. (iii) Gravitational PE depends on. (iv) Translational KE depends on ____ variables. (v) Energy is stored due to ____ forces of the Earth. (vi) The forms of kinetic energy. (vii) In KE, motion can be. (viii) Energy of motion. (x) Energy is measured in.
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Answer: (i) (a) scalar; (ii) (a) second; (iii) (c) both mass and height; (iv) (b) two (mass and speed); (v) (a) gravitational; (vi) (d) all of these; (vii) (d) both vertical and horizontal; (viii) (c) kinetic energy; (x) (c) newton-metres (joules).
Teacher's Note: Remember this for your exam.
20. Fill in the blanks: 1. ____ is done when a force moves an object. 2. The ability to do work is ____. 3. An object can do ____ equal to the energy it has. 4. The ground is a position of ____ height. 5. The rate of doing work is ____. 6. The energy of a non-moving object due to its position is ____. 7. In photosynthesis light energy changes to ____ energy. 9. If the height is doubled, gravitational PE is ____. 10. Kinetic energy is a ____ quantity.
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Answer: 1. Work; 2. energy; 3. work; 4. zero; 5. power; 6. potential energy; 7. chemical; 9. doubled; 10. scalar.
Teacher's Note: Learn this point and write it in your own words.
21. True or False: 1. If the mass is doubled, the kinetic energy increases four times. 2. Energy does not occur in various forms. 3. KE is inversely proportional to the square of velocity. 4. We need energy to cook food. 5. Work is only done when the object moves. 6. An object can do more work than the energy it has. 7. Energy transformation occurs in daily activities. 8. We can store power. 9. KE has magnitude and direction. 10. A lighter object has more gravitational PE.
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Answer: 1. False (it is doubled); 2. False; 3. False (it is directly proportional to the square of speed); 4. True; 5. True; 6. False; 7. True; 8. False; 9. False (it is a scalar); 10. False.
Teacher's Note: Use the key term in your answer.
22. Match: 1 kinetic energy 2 types of PE 3 standard unit of energy 4 energy and work 5 unit of power 6 gravitational PE 7 work 8 law of conservation of energy 9 listening to music on an iPod 10 energy transformation.
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Answer:
| Item | Match |
|---|---|
| 1 | d. 1/2 x m x v squared |
| 2 | e. Gravitational, elastic and electric PE |
| 3 | h. Joule |
| 4 | b. Analogous |
| 5 | c. Watt |
| 6 | j. mass x g x height |
| 7 | i. Force x displacement |
| 8 | f. Energy is conserved and changes from one form to another |
| 9 | a. Electrical energy to sound energy |
| 10 | g. Done constantly |
Teacher's Note: Give an example if the question allows.
23. F1. Kinetic energy of a 4 kg body moving at 0.2 m/s. What if the velocity is doubled? F2. PE of a 4 kg body at a height of 3 m (g = 10). F3. Work done by a 40 N force over 2 m. F4. The KE of a 4 kg volleyball that travels 40 m in 2 s.
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Answer: F1. KE = 1/2 x 4 x 0.04 = 0.08 J. At 0.4 m/s, KE = 1/2 x 4 x 0.16 = 0.32 J, which is four times the earlier value. F2. PE = 4 x 10 x 3 = 120 J. F3. W = 40 x 2 = 80 J. F4. Speed = 40 / 2 = 20 m/s, so KE = 1/2 x 4 x 400 = 800 J.
Teacher's Note: Write a short, clear answer.
Free study material for Science
Download CBSE Practice Material: Class 8 Science Energy
Energy Printable Worksheet for Class 8 Science
Explore reliable practice questions for Energy tailored for Class 8 Science learners. Use these structured worksheets to evaluate preparedness and strengthen problem-solving skills.
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FAQs
You can download the teacher-verified PDF for CBSE Class 8 Science Energy Worksheet Set 04 from StudiesToday.com. These practice sheets for Class 8 Science are designed as per the latest CBSE academic session.
Yes, our CBSE Class 8 Science Energy Worksheet Set 04 includes a variety of questions like Case-based studies, Assertion-Reasoning, and MCQs as per the 50% competency-based weightage in the latest curriculum for Class 8.
Yes, we have provided detailed solutions for CBSE Class 8 Science Energy Worksheet Set 04 to help Class 8 and follow the official CBSE marking scheme.
Daily practice with these Science worksheets helps in identifying understanding gaps. It also improves question solving speed and ensures that Class 8 students get more marks in CBSE exams.
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