Question
Physics Question on thermal properties of matter
A cylindrical rod having temperature T1 and T2 at its end. The rate of flow of heat Q1 cal/sec. If all the linear dimension are doubled keeping temperature remain const. then rate of flow of heat Q2 will be
A
4Q1
B
2Q1
C
Q1/4
D
Q1/2
Answer
2Q1
Explanation
Solution
The correct option is(B) 2Q1 Heat flow rate =KA(T1 T2)/L=Q when linear dimensions are doubled A1 ∝ r1^2, L1 = L, A2 ∝ 4r1^2, L1 = 2L1 so Q2 = 2Q1