There indectical thermal conductors are connected as shown in Fig. 7(CF).17. Considering no heat is lost due to radition, the temperature of the junction is

Options

A. `60^(@)C`
B. `20^(@)C`
C. `50^(@)C`
D. `10^(@)C`

Answer

C

Explanation

Let `theta^(@)C` be the temperature of junction
`(kA(60^(@) - theta))/(x) + (kA(70^(@) - theta))/(x) = (kA(theta - 20^(@)))/(x)`
`60^(@) - theta + 70^(@) - theta=thata - 20^(@)`
`150^(@) =3 theta` or `thata=50^(@)C`