If l is the length, A is the area of cross-section and K the thermal conductivity, then the thermal resistance of the block is given by

Options

A. `(Kl)/(A)`
B. `(l)/(KA)`
C. `(AK)/(l)`
D. `(A)/(Kl)`

Answer

B

Explanation

`Q=(KA(theta_(1)-theta_(2)))/(l) or Q/l = (theta_(1)-theta_(2))/(l//KA)`
Compare with `I = V/R`
So, thermal resistance = `l/(KR)`.