Question

Rate of flow of heat through a cylindrical rod is \( H_1 \). The temperature of the ends of the rod are ' \( T_1 \) ' and ' \( T_2 \) '. If all the dimensions of the rod become double and the temperature difference remains the same, the rate of flow of heat becomes ' \( H_2 \) '. Then \( H_2 = \)

• A. \( \frac{H_1}{2} \)
• B. \( 2H_1 \)
• C. \( \frac{H_1}{4} \)
• D. \( 4H_1 \)

Hint:

- Heat flow $\propto \frac{A}{L}$ - If dimensions double: $A \rightarrow 4A$, $L \rightarrow 2L$ - Net effect $\Rightarrow$ heat flow doubles

Answer 1

The Correct Option is B