A steel wire of uniform cross- sectional area $2\;mm^2$ in heated upto $50^{\circ}C$ and is stretched by clamping its two ends rigidly. The change in tension when the temperature falls from $50^{\circ}C$ to $30^{\circ}C$ is $( \alpha =1.1 \times 10^{-5} C)\;(Y=2.0 \times 10^{11} N/ m^2)$

Question

\[\begin {array} {1 1} (a)\;88\;N \\ (b)\;5\;N \\ (c)\;1.5 \times 10^{10}\;N \\ (d)\;2.5 \times 2.5 \times 10^{10} \;N \end {array}\]