Physics Elasticity Question 158

Question: The area of cross section of a steel wire $ (Y=2.0\times 10^{11}N/m^{2}) $ is $ 0.1\ cm^{2} $ . The force required to double its length will be

[MP PET 2002]

Options:

A) $ 2\times 10^{12}N $

B)$ 2\times 10^{11}N $

C) $ 2\times 10^{10}N $

D)$ 2\times 10^{6}N $

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Answer:

Correct Answer: D

Solution:

When the length of wire is doubled then $ l=L $ and strain = 1 \ Y = strain =$ \frac{F}{A} $ Force = Y × A $ =2\times 10^{11}\times 0.1\times {{10}^{-4}} $

$ =2\times 10^{6}N $