Let θ be the temperature at point C at a distance x from end A of the bar whose ends arekept at temperatures θ1 and θ2 with θ1>θ2 . L – length of the bar. In steady state, the rate of flow of heat from A to C = rate of heat flow from C to B i.e.,
KA(θ1−θ)
x
=
KA(θ−θ2)
L−x
⇒ θ = θ1 - (
θ1−θ2
L
) x Thus, the graph of θ versus x is a straight line with a positive intercept and negative slope.