AIIMS 2017 Physics Question Paper for free online practice with solutions

The temperature of the two outer surfaces of a composite slab consisting of two materials having coefficient of thermal conductivity K and 2K and thickness x and 4x respectively are T2 and T1(T2>T1). The rate of heat transfer through the slab, in a steady state is (

A(T2−T1)K

x

)f with f equal to