GS PrelimsScience and TechnologyGeneral Science2001

Assertion (A): A piece of copper and a piece of glass are heated to the same temperature. When touched, thereafter, the copper piece appears hotter than the glass piece. Reason (R): The density of copper is more than that of glass.

A

Both A and R are individually true and R is the correct explanation of A

B

Both A and R are individually true but R is NOT a correct explanation of A

C

A is true but R is false

D

A is false but R is true

Correct Answer: Option B

Explanation

1. Assertion (A): A piece of copper and a piece of glass are heated to the same temperature. When touched, the copper piece appears hotter than the glass piece. This statement is true. 2. The reason for this perception is related to thermal conductivity. Copper is a good thermal conductor, while glass is a poor thermal conductor (insulator). When touched, the copper transfers heat to the hand much more quickly than glass does, making it feel hotter, even though both are at the same initial temperature. 3. Reason (R): The density of copper is more than that of glass. This statement is also true (Density of Copper ≈ 8.96 g/cm³, Density of Glass ≈ 2.5 g/cm³). 4. However, the higher density of copper is not the correct explanation for why it feels hotter. The correct explanation involves its higher thermal conductivity. 5. Therefore, both Assertion (A) and Reason (R) are individually true, but Reason (R) is NOT the correct explanation of Assertion (A).

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