Transmission Of Heat Question 34
Question: The ratio of thermal conductivity of two rods of different material is 5 : 4. The two rods of same area of cross-section and same thermal resistance will have the lengths in the ratio
[MP PET 1984; BVP 2003]
Options:
A) 4 : 5
B) 9 : 1
C) 1 : 9
D) 5 : 4
Show Answer
Answer:
Correct Answer: D
Solution:
Given $ A _{1}=A _{2} $ and $ \frac{K _{1}}{K _{2}}=\frac{5}{4} $ Q $ R _{1}=R _{2}\Rightarrow $
$ \frac{l _{1}}{K _{1}A}=\frac{l _{2}}{K _{2}A} $
Therefore $ \frac{l _{1}}{l _{2}}=\frac{K _{1}}{K _{2}}=\frac{5}{4}. $
BETA
