COMPLETION TYPE QUESTIONS The Young's modulus of a wire of length L and radius r is Y. If the length is reduced to L/ 4 and radius r/4, then its Young's modulus will be_______.

Options

A. `(4)/(3)Y`
B. `(3)/(4)Y`
C. 3Y
D. 4Y

Answer

A

Explanation

`T= (Fxx L)/(A xx Delta L) Y prop (L)/(A) rArr Y prop (L)/(r^(2))`
`therefore (Y_(1))/(Y_(2))= (L)/(r_(2)) xx (3)/(L) xx (r^(2))/(4)= (3)/(4 ) rArr Y_(2)= (4)/(3)Y`