Q.20 A steel rod (Y=2.0×1011 N/m2 and α=10-50 °C-1) of length 1 m and area of cross-section 1 cm2 is heated from 0°C to 200°C without being allowed to extend to bend. What is the tension produced in the rod?

Hint: The tension produced in the rod can be calculated by the stress developed in the wire.
Step 1: Find the tension produced in the wire.
Given, Young's modulus of steel, Y =2.0×1011 N/m2
Coefficient of thermal expansion, α=10-5 °C-1
Length, l=1m
Area of cross-section, A =1Cm2=1×10-4 m2
Increases in temperature, T=200°C-0°C=200°C
The tension produced in steel rod(F) = YAαT
                                                     =2.0×1011×1×10-4×10-5×200
=4×104N