A cylindrical wire of radius 1 mm and length 1 m has Young's modulus 2×10¹¹ N m⁻² and Poisson ratio μ=π/10. It is stretched by a force of 100 N. Its new radius is:
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A cylindrical wire of radius 1 mm and length 1 m has Young's modulus 2×10¹¹ N m⁻² and Poisson ratio μ=π/10. It is stretched by a force of 100 N. Its new radius is:

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 D: 0.99995 mm. Therefore the correct answer is D.