Question

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

• A.
• B.
• C.
• D.

Answer 1

Answer: (B)

Answer 2

From Fourier's law of heat conduction

$\frac{dQ}{dt}$= – KA$\frac{d\theta}{dx}$

$\because$ $\frac{d\theta}{dt}$= rate of heat flow = const.

\ $\frac{d\theta}{dx}$ = – const.

Thus, graph b/w temperature (q) and distance (x) is a straight line of negative slope.

Which is

option (2).