The wall with a cavity consists of two layers of brick separated by a layer of air All three lay-ers have the same thickness and the thermal conductivity of the brick is much greater than that of air The left layer is at a higher temperature than the tight layer and steady state condition exists Which of the following graphs perdicts correctly the variation of temperature `T` with distance d inside the cavity ?.

Options

A.
B.
C.
D.

Answer

D

Explanation

`(dQ)/(dt) =KA (d theta)/(dx)`
`(d theta)/(dx) =` slope of graph `alpha (1)/(K)` .