The ends of a metre stick are maintained at `100^(@)C` and `0^(@)C`. One end of a rod is maintained at `25^(@)C`. Where should its other end be touched on the metre stick so that there is no heat current in the rod in steady state?

Options

A. `25 cm` form the hot end
B. `40 cm` from the cold end
C. `25 cm` from the cold end
D. `60 cm` from the cold end

Answer

C

Explanation

`25 cm` from cold end is at `25^(@)C` (Since temperature gradient is `1^(@)C//cm)`
`:.` rod shound be touched at this point to ensure no heat transfter.