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Heat transfer through a composite wall is shown in figure. Both the sections of the wall have equal thickness (/). The conductivity of one section is k and that of the other is 2k. The left face of the wall is at 600 K and the right face is at 300 K.
The interface temperature Ti (in K) of the composite wall is __________
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- 400 K
- 600 K
- 700 K
- 800 K
Correct Option: A
R = R1 + R2
| = | + | = | + | = | ||||||
| KA | KA | KA | 2KA | 2KA |
| Q = | TR |
| = | = 200 × | ||
| L | |||
| 2KA |
At interface,
| Q = | Ti |
| = | = (600 - Ti) | ||
| L | |||
| KA |
| 200 | = (600 - Ti) | ||
| L | L |
200 = 600 – Ti
Ti = 400 K
