Flow of heat through a composite conductor
(a)Temperature of interface, θ =(k1$1/d1)+(k2$2/d2)/(k1/d1+k2/d2)
(b)Rate of flow of heat through the composite conductor: H = Q/T=A($1-$2)/(d1/k1+d2/k2)
(c)Thermal resistance of the composite conductor=
Rth=d1/k1a+d2/k2a=(Rth)1+(Rth)2
(d)Equivalent thermal conductivity, K =d1+d2/(d1/k1)+(d2/k2)