Two ends of a conducting rod of varying cross-section are maintained at `200^(@)C` and `0^(@)C` respectively. In steady state:

Options

A. temperature difference across `AB` and `CD` are equal
B. temperature difference across `AB` and `CD`
C. temperature difference across `AB` and `CD`
D. temperature difference may be equal or differnet depeding on the thermal conductivity of the rod .

Answer

C

Explanation

`Deltatheta=(Q)/(t)xx` thermal resistance
`Delta theta prop` thermal resistance `(R )` where `R =(l)/(KA)`
`Delta theta prop (1)/(A)` Area across `CD` is less Therefore temperature difference across `CD` will be more .