Transmission Of Heat Question 107
Question: Three rods of the same dimension have thermal conductivities 3K, 2K and K. They are arranged as shown in fig. Given below, with their ends at 100oC, 50oC and 20oC. The temperature of their junction is
[UPSEAT 2002]
Options:
A) $ 60^{o} $ C
B) $ 70^{o} $ C
C) 50o C
D) 35o C
Show Answer
Answer:
Correct Answer: B
Solution:
Let the temperature of junction be q then according to following figure. H = H1 + H2
Therefore $ \frac{3K\times A\times (100-\theta )}{l}=\frac{2KA(\theta -50)}{l}+\frac{KA(\theta -20)}{l} $
Therefore 300 ? 3q = 3q ? 120
Therefore q = 70°C
BETA
