Important Questions of Work, Energy and Power for CBSE Class XI Physics

Work, Power, and Energy - Important Questions

1. Define work. What are the conditions under which work is done?

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2. What is the work-energy theorem? Derive it for a constant force.

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3. A force of 50 N is applied at an angle of 30° to the horizontal on a block moving on a frictionless surface. Calculate the work done by the force in moving the block by 10 meters.

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4. Define potential energy and kinetic energy. Derive the expression for gravitational potential energy.

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5. Explain the law of conservation of mechanical energy with an example.

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6. A ball of mass 2 kg is dropped from a height of 10 meters. Calculate the velocity with which it strikes the ground and the kinetic energy just before impact.

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7. Differentiate between conservative and non-conservative forces with examples.

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8. What is power? Derive an expression for power in terms of force and velocity.

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9. Two objects of masses 2 kg and 3 kg are moving with velocities 5 m/s and 4 m/s, respectively. Calculate their kinetic energies and the total energy of the system.

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10. State and explain the concept of elastic and inelastic collisions.

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11. A spring with a spring constant of 500 N/m is compressed by 10 cm. Calculate the potential energy stored in the spring.

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12. What is meant by power efficiency?

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13. Explain how to calculate the work done by a variable force.

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14. Derive the relationship between kinetic energy and momentum for a moving object.

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15. What is the significance of negative work? Provide examples where work done is negative.

Important Questions of Work, Energy, and Power for CBSE Class XI Physics

The chapter Work, Energy, and Power plays a key role in Class 11 Physics. It builds the foundation for advanced concepts in mechanics and is equally crucial for NEET, JEE, and other competitive exams. Mastering this topic involves not just understanding the theory but also practicing important questions.

Why Focus on Work, Energy, and Power?

This chapter introduces key concepts that are frequently tested in exams. Below are the main topics:

• Calculating work done under constant and variable forces.
• Kinetic and potential energy with real-world applications.
• Understanding power and energy transfer rates.
• Work-energy theorem and conservation of energy.

Class 11 Physics Work, Energy, and Power Important Questions

Here are some important questions to help you prepare:

• What is work? Derive the formula for work done when force is applied at an angle.
• Explain the concept of kinetic energy and derive \(KE = \frac{1}{2} mv^2\).
• State and prove the work-energy theorem.
• What is potential energy? Derive the formula for gravitational potential energy.
• Explain the law of conservation of energy with an example.

Work, Energy, and Power Class 11 Important Questions with Answers

Below are some questions with solutions to help you practice effectively:

• Q: A force of 10 N is applied to move a block over a distance of 5 m. Calculate the work done.
  Answer: \(W = F \times d = 10 \times 5 = 50 \, J\)


• Q: What is the power of a machine that performs 200 J of work in 5 seconds?
  Answer: \(P = \frac{W}{t} = \frac{200}{5} = 40 \, W\)


• Q: Calculate the potential energy of a 10 kg object placed at a height of 10 m. (Take \(g = 9.8 \, m/s^2\))
  Answer: \(PE = mgh = 10 \times 9.8 \times 10 = 980 \, J\)

Work Power Energy MCQ for Competitive Exams

Practicing multiple-choice questions (MCQs) for this topic is essential for competitive exams. Make sure to focus on questions involving:

• Work done by variable forces.
• Applications of the work-energy theorem.
• Efficiency and power output of machines.

Conclusion

Practicing important questions for class 11 physics work energy and power will build your confidence and understanding of the subject. These questions not only prepare you for board exams but also help with competitive exams like NEET. You can also download work energy and power class 11 important questions with answers PDF to revise easily.