Two rods A and B are of equal lengths. Their ends are kept at the same temperature difference and their area of cross - sections are `A_(1)` and `A_(2)` and thermal conductivities `k_(1)` and `k_(2)`. The rate of heat transmission in two rods will be equal, if . . . .. . .

Options

A. `k_(1)A_(2)=k_(2)A_(1)`
B. `k_(1)A_(1)=k_(2)A_(2)`
C. `k_(1)=k_(2)`
D. `k_(1)A_(1)^(2)=k_(2)A_(2)^(2)`

Answer

B

Explanation

`H_(1)=H_(2)`
`:.k_(1)A_(1)((T_(1)-T_(2))/(L))=k_(2)A_(2)((T_(1)-T_(2))/(L))`
`:.k_(1)A_(1)=k_(2)A_(2)`