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°C is : (For steel Young's modulus is 2 ×10¹¹ N m⁻² and coefficient of thermal expansion is 1.1 ×10⁻⁵ K⁻¹)
Options

Question

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°C is : (For steel Young's modulus is 2 ×10¹¹ N m⁻² and coefficient of thermal expansion is 1.1 ×10⁻⁵ K⁻¹)

Options

G1 Physics · Accepted Answer

Use stress σ=F/A, strain ε=ΔL/L and Young's modulus Y=σ/ε. For a uniform segment, ΔL=FL/(AY); for thermal restraint, thermal strain αΔT produces stress YαΔT. Evaluating the given data/statements gives 2.2 ×10⁸ Pa. Therefore the correct answer is C.