Moderate

A student touches the metal surface of a hot calorimetre. He is likely to burn his hand. If he holds his hand in the hot air inside the calorimetre, then he will remain fine. Which of the following statements BEST describe the given condition?

Correct answer: C. Metal is a good conductor, but air is a poor conductor of heat.

  • A. Both the metal and air are poor conductor of heat.
  • B. Both the metal and air are good conductors of heat.
  • C. Metal is a good conductor, but air is a poor conductor of heat.
  • D. Air is a good conductor, but metal is a poor conductor of heat.

Explanation

The problem describes a scenario where touching the metal surface of a hot calorimeter causes a burn, but holding a hand in the hot air inside does not. This indicates a difference in how well metal and air conduct heat. Metals are generally good conductors of heat, meaning they transfer thermal energy efficiently, which is why touching a hot metal surface can cause a burn. Air, on the other hand, is a poor conductor of heat (an insulator), meaning it does not transfer thermal energy as efficiently, hence holding a hand in hot air might not cause a burn even if the air is at a high temperature.

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About Thermal Equilibrium and Heat

Thermal equilibrium means that bodies in contact have the same temperature and no net heat flows between them. The topic distinguishes heat from temperature, uses the zeroth law of thermodynamics, and covers heat transfer, specific heat capacity, thermal expansion and the conditions for reaching equilibrium.

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