The temperature at the two ends A and B of a rod of length 25 cm and circular cross section are $100^{\circ}C \: and \: 0^{\circ}C$ respectively. In the steady state the temperature at a point 10 cm from the end B is ( Ignore loss of heat from curved surface of the rod )
$\begin {array} {1 1} (1)\;60^{\circ}C & \quad (2)\;80^{\circ}C \\ (3)\;90^{\circ}C & \quad (4)\;40^{\circ}C \end {array}$
(4) $40^{\circ}C$