Which expression gives the rate at which thermal energy is conducted through a…

PHYSICS · Single correct · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics

Problem

Which expression gives the rate

P

at which thermal energy is conducted through a uniform rod of length

L

and cross-sectional area

A

with thermal conductivity

k

when its ends are maintained at temperatures

T_1

and

T_2

(

T_1 > T_2

)? (a)

P=\dfrac{2kA\,(T_1-T_2)}{L}

(b)

P=\dfrac{kA\,(T_1-T_2)}{L}

(c)

P=\dfrac{kA\,(T_1-T_2)}{2L}

(d)

P=\dfrac{kA\,\ln\!\left(\dfrac{T_1}{T_2}\right)}{L}