The coefficient of thermal conductivity of copper, mercury and glass are respectively `K_(c), K_(m)` and `K_(g)` that `K_(c) gt K_(m) gt K_(g)`. If the same quantity of heat is to flow per second per unit of each and corresponding temperature gradients are `X_(c), X_(m)` and `X_(g)`, then

Options

A. `X_(c) =X_(m) =X_(g)`
B. `X_(c)lt x_(m) lt X_(g)`
C. `x_(c) gt x_(m) gtX_(g)`
D. `X_(m)lt X_(c) lt X_(g)`

Answer

C

Explanation

`Q=(KA(Deltatheta)t)/(l)rArrK((Deltatheta)/(l))=const`
`((Deltatheta)/(l))prop(1)/(K)rrArrXprop(1)/(K),"Since",K_(3)gtK_(m)gtK_(g)`
For same quantity of heat flow per sec per unit area of each `X_(c) lt X_(m) lt X_(g)` .