Transmission Of Heat Question 38
Question: Two rods A and B are of equal lengths. Their ends are kept between the same temperature and their area of cross-sections are $ A _{1} $ and $ A _{2} $ and thermal conductivities $ K _{1} $ and $ K _{2} $ . The rate of heat transmission in the two rods will be equal, if
[MP PMT 1991; CBSE PMT 2002]
Options:
A) $ K _{1}A _{2}=K _{2}A _{1} $
B) $ K _{1}A _{1}=K _{2}A _{2} $
C) $ K _{1}=K _{2} $
D) $ K _{1}A _{1}^{2}=K _{2}A _{2}^{2} $
Show Answer
Answer:
Correct Answer: B
Solution:
$ {{( \frac{Q}{t} )} _{1}}=\frac{K _{1}A _{1}({\theta _{1}}-{\theta _{2}})}{l} $ and $ {{( \frac{Q}{t} )} _{2}}=\frac{K _{2}A _{2}({\theta _{1}}-{\theta _{2}})}{l} $ given $ {{( \frac{Q}{t} )} _{1}}={{( \frac{Q}{t} )} _{2}} $
Therefore $ K _{1}A _{1}=K _{2}A _{2} $
BETA
