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 `100^(@)C, 50^(@)C` and `20^(@)C`. The temperature of their junction is :-

Answer

`70.00`

Explanation

Let the temperature of junction be `theta` then according to the following figure.

`H=H_(1)+H_(2)`
`rArr (3K xx A xx(100-theta))/(1)=(2KA(theta-50))/(1)+(KA(theta-20))/(1)`
`rArr 300-3theta=3theta-120 rArr theta = 70^(@)C`