The two ends of a rod of length `L` and a uniform cross-sectional area `A` are kept at two temperature `T_(1)` and `T_(2)` `(T_(1) gt T_(2))`. The rate of heat transfer. `(dQ)/(dt)`, through the rod in a steady state is given by

Options

A. `(dQ)/(dt)=(KL(T_1-T_2))/(A)`
B. `(dQ)/(dt)=(K(T_1-T_2))/(LA)`
C. `(dQ)/(dt)=KLA(T_1-T_2)`
D. `(dQ)/(dt)=(KA(T_1 - T_2))/(L)`

Answer

D

Explanation

In steady state the heat flow from one face to other face is given by `(dQ)/(dt)=q=(-K(T_2-T-1)A)/(L)`