A metal rod of Young's modulus `2 xx 10^(10) Nm^(-2)` undergoes elastic strain of 0.06%. The energy per unit volume stored (in `Jm^(-3)`) is

Options

A. 3600
B. 7200
C. 10800
D. 14400

Answer

a

Explanation

As energy volume `= (1)/(2) xx` stress `xx` strain
` = (1)/(2) Y xx` strain `xx` strain `= (1)/(2) Y xx "strain"^(2)`
`(1)/(2) xx 2 xx 10^(10) xx 0.06 xx 10^(-2) xx 0.06 xx 10^(-2) = 3600 Jm^(-3)`