Physics Elasticity Question 143

Question: A steel wire of lm long and $ 1,mm^{2} $ cross section area is hang from rigid end. When weight of 1kg is hung from it then change in length will be (given $ Y=2\times 10^{11}N/m^{2}) $

[RPMT 2000]

Options:

A) 0.5 mm

B)0.25 mm

C) 0.05 mm

D)5 mm

Show Answer

Answer:

Correct Answer: C

Solution:

$ l=\frac{MgL}{YA}=\frac{1\times 10\times 1}{2\times 10^{11}\times {{10}^{-6}}}=0.05\ mm $