Calculate the compressional force required to prevent the metallic rod of length l cm and cross-sectional area A cm² when heated through t°C, from expanding along length wise. The Young's modulus of elasticity of the metal is E and mean coefficient of linear expansion is a per degree Celsius

• A

  EAαt

• B

  $\frac{\mathrm{EA\alpha t}}{1+\mathrm{\alpha t}}$

• C

  $\frac{\mathrm{EA\alpha t}}{1-\mathrm{\alpha t}}$

• D

  Elαt