Twelve conducting rods from the sides of a uniform cube of side l. If in steady state, `B` and `H` ends of the cube are at `100^(@)C` and `0^(@)C` respectively. Find the temperature of the junction `'A'` :-

Options

A. `80^(@)C`
B. `60^(@)C`
C. `40^(@)C`
D. `70^(@)C`

Answer

B

Explanation

For the cube , net resistance = `(5R)/(6)`
(Where `R`= thermal resistance of each side)
` H=(100-0)/(5R//6)`
For side `A`
`(H)/(3) = (100-theta_(A))/(R) implies theta_(A) = 60^(@)C`