The young's modulus of the material of a wire is `2 times 10^8 Nm^-2`. If the elongation strain is 1%, then the energy stored in the wire per unit volume in `Jm^-3` us

Options

A. a)`10^6`
B. b)`10^8`
C. c)`2 times 10^6`
D. d)`2 times 10^8`

Answer

A

Explanation

Per unit volume energy stored `=1/2 times Y times (strain)^2`
`=1/2 times Y times (l/L)^2`
Given `l=L times 1%`
or `l=L/100`
Stored energy `Y=1/2 times 2 times 10^10 times (L/(100l))^2`
`=10^6 Jm^-3`