Cylinder rod of copper of length `2m` and cross-sectional area `2cm^(2)` is insulated at its curved surface. The one end of rod is maintained in steam chamgber and other is maintained in ice at `0^(@)C` (The thermal coductivity of copper is `386J//m-s .^(@)C`). Find the temperature at a point which is at a distance of `120cm` from the colder end.

Options

A. `80^(@)C`
B. `60^(@)C`
C. `50^(@)C`
D. none of the above

Explanation

(b) In steady state, temperature gradient of rod remains constant.

`:. (100^(@)-theta)/80=(theta-0)/120`
or `100^(@)-theta=(80/120)theta`
or `100^(@)-theta=2/3theta` or `100^(@)=5/3theta`
`:. theta=(100xx3)/5=60^(@)C`