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QPages 97-98: Q4: HC Verma: Concepts of Physics - Volume 2 Heat Transfer Pages 97-98: Q4 Solution: A piece of charcoal and a piece of shining steel of the same…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students often equate a material’s higher thermal conductivity with a higher steady‑state temperature or greater heat absorption, but the felt hotness depends on how quickly heat is transferred to the hand, not on the final temperature. Remember that $k$ (thermal conductivity) governs the rate of heat flow, while temperature rise is governed by heat capacity and radiative balance.

A piece of charcoal and a piece of shining steel of the same surface area are kept for a long time in an open lawn in bright sun.

Multiple Choice Options

  • A The steel will absorb more heat than the charcoal.
  • B The temperature of the steel will be higher than that of the charcoal.
  • C If both are picked up by bare hand, the steel will be felt hotter than the charcoal.
  • D If the two are picked up from the lawn and kept in a cold chamber, the charcoal will lose heat at a faster rate than the steel.

Step-by-Step Verified Solution

**Answer:** (c) If both are picked up by bare hand, the steel will be felt hotter than the charcoal. **Step-by-Step Explanation:** Steel has higher thermal conductivity than charcoal, so it conducts heat to the hand faster, feeling hotter.

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