Physics Elasticity Question 87

Question: The diameter of a brass rod is 4 mm and Young’s modulus of brass is $ 9\times 10^{10},N/m^{2} $ . The force required to stretch by 0.1% of its length is

[MP PET 1991; BVP 2003]

Options:

A) $ 360,\pi N $

B) 36 N

C) $ 144\pi \times 10^{3}N $

D) $ 36\pi \times 10^{5}N $

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Answer:

Correct Answer: A

Solution:

$ F=\frac{YAl}{L}=\frac{9\times 10^{10}\times \pi \times 4\times {{10}^{-6}}\times 0.1}{100}=360\ \pi \ N $