Physics Elasticity Question 67

Question: A wire of length 50 cm and cross sectional area of 1 sq. mm is extended by 1 mm. The required work will be $ (Y=2\times 10^{10},N{{m}^{-2}}) $

[RPET 1999]

Options:

A) $ 6\times {{10}^{-2}},J $

B) $ 4\times {{10}^{-2}},J $

C) $ 2\times {{10}^{-2}},J $

D) $ 1\times {{10}^{-2}},J $

Show Answer

Answer:

Correct Answer: C

Solution:

$ W=\frac{YAl^{2}}{2L}=\frac{2\times 10^{10}\times {{10}^{-6}}\times {{({{10}^{-3}})}^{2}}}{2\times 50\times {{10}^{-2}}} $

$ =2\times {{10}^{-2}}\ J $