A long metallic bar is carrying heat from one of its ends to the other end under steady-state. The variation of temperature `theta` along the length x of the bar from its hot end is best described by which of the following figure.

Options

A.
B.
C.
D.

Answer

B

Explanation

We have that `(dQ)/(dt)=KA(d theta)/(dx)`
In steady state flow of heat,
`d theta=(dQ)/(dt)xx(1)/(KA)xxdxrArrtheta_(H)-thetakxrArrtheta=theta_(H)-k'x`
(where is some constant)
The equation `theta=theta_(H)-K'x` represents a straight line