Question

A composite slab has two layers of different materials with thermal conductivities 1 k and 2 k . If each layer has same thickness, then the equivalent thermal conductivity will be:

Answer 1

A composite slab has two layers of different materials with thermal conductivity K1 and K2 . If each layer has same thickness , the equivalent thermal conductivity of the slab would be _

Answer

2K1K2/K1+K2

Answer 2

1/keq=1/k+1/2k=3/2k

keq=2k/3