A long metallic bar is carrying heat from on eof 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 figures?

Options

A.
B.
C.
D.

Answer

A

Explanation

(a) The heat flow rate is given by
`(dQ)/(dt)=(KA( theta_1-theta))/x`
`rArr theta_1-theta=x/(KA) (dQ)/(dt) rArr theta=theta_1-x/(kA) (dQ)/(dt)`
Where is `theta_1` is the temperature of hot end and `theta` is
temperature at a distance x from hot end.
The above equation can be graphically represented by
Option (a)