The pressure that has to be applied to the ends of a steel wire of length 10 cm to keep its length constant when its temperature is raised by $\;100^{0}C\;$ : (For steel Young's modulus is $\;2 \times 10^{11} Nm^{-2}\;$ and coefficient of thermal expansion $\;1.1 \times 10^{-5} K^{-1}\;$)