Question

Assertion :According to Newton's law, good conductors of electricity are also good conductors of heat. Reason: At a given temperature, $e_{\lambda }\propto a_{\lambda }$ for any body.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is D Assertion is incorrect but Reason is correct

Newton's law in heat transfer relates the rate of change of temperature(absolute) of a body to the temperature difference between the body and its surroundings.
$\frac{dT}{dt}=-bA(T-T_0)$
It doesn't say anything about whether a good conductor of heat is also a good conductor of electricity. Hence the Assertion is False.
The absorptive power is always equal to the emissive power of a body.
$e_{\lambda }=a_{\lambda }$
So the reason is True.