Verified Solution • 2025–26 Session moderate

QPage 12: Q2: HC Verma: Concepts of Physics - Volume 2 Heat and Temperature Page 12: Q2 Solution: A spinning wheel is brought in contact with another wheel ,…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students frequently assume that the kinetic gain of wheel B means the system’s total energy rises, neglecting that the work of friction converts part of the mechanical work into internal (thermal) energy of the wheels. Remember: kinetic + mechanical energy of B increase, but an equal amount of mechanical energy is lost as internal energy, so the total energy of the isolated system stays constant.

A spinning wheel AA is brought in contact with another wheel BB, initially at rest. Because of the friction at contact, the second wheel also starts spinning. Which of the following energies of the wheel BB increases?

Multiple Choice Options

  • A a) Kinetic
  • B b) Total
  • C c) Mechanical
  • D d) Internal

Step-by-Step Verified Solution

**Answer:** a), c), d) increase. **Step-by-Step Explanation:** For wheel B initially at rest, when it starts spinning, its kinetic energy increases. Mechanical energy increases (from zero to some value). Internal energy also increases due to friction. Total energy remains constant (energy conservation). So a), c), d) increase. Total energy does not change.

All Questions in this Chapter

QPage 11: Q1 QPage 11: Q2 QPage 11: Q3 QPage 11: Q4 QPage 11: Q5 QPage 11: Q6 QPage 11: Q7 QPage 11: Q8 QPage 11: Q9 QPage 11: Q10 QPage 11: Q11 QPage 11: Q12 QPage 11: Q13 QPage 12: Q1 QPage 12: Q2 QPage 12: Q3 QPage 12: Q4 QPage 12: Q5 QPage 12: Q6 QPages 11-12: Q1 QPages 11-12: Q2 QPages 11-12: Q3 QPages 11-12: Q4 QPages 11-12: Q5 QPages 11-12: Q6 QPages 11-12: Q7 QPages 11-12: Q8 QPages 11-12: Q9 QPages 11-12: Q10 QPages 11-12: Q11 QPages 12-14: Q1 QPages 12-14: Q2 QPages 12-14: Q3 QPages 12-14: Q4 QPages 12-14: Q5 QPages 12-14: Q6 QPages 12-14: Q7 QPages 12-14: Q8 QPages 12-14: Q9 QPages 12-14: Q10 QPages 12-14: Q11 QPages 12-14: Q12 QPages 12-14: Q13 QPages 12-14: Q14 QPages 12-14: Q15 QPages 12-14: Q16 QPages 12-14: Q17 QPages 12-14: Q18 QPages 12-14: Q19 QPages 12-14: Q20 QPages 12-14: Q21 QPages 12-14: Q22 QPages 12-14: Q23 QPages 12-14: Q24 QPages 12-14: Q25 QPages 12-14: Q26 QPages 12-14: Q27 QPages 12-14: Q28 QPages 12-14: Q29 QPages 12-14: Q30 QPages 12-14: Q31 QPages 12-14: Q32 QPages 12-14: Q33 QPages 12-14: Q34

Related Learning Resources & Exam Preparation

Chapter Practice Bank
Practice all topic-wise questions from Heat and Temperature
Reference Textbook Solutions
Explore complete chapter exercises for HC Verma: Concepts of Physics - Volume 2
Competitive PYQ Question Bank
Browse year-wise authentic previous years' questions with solutions
Authentic CBT Mock Tests
Simulate official exam environment with live timer and percentile scoring