A long elastic spring is stretched by `2 cm` and its potential energy is `U`. If the spring is stretched by `10 cm`, the `PE` will be

Options

A. 5 U
B. 25 U
C. `(U)/(5)`
D. `(U)/(20)`

Answer

B

Explanation

The elastic pot. Energy `=(1)/(2)str essxx"strain"`
`=(1)/(2)Y("strain")^2=(1)/(2)Y((trianglel)/(L))^2`
`(U_2)/(U_2)prop((trianglel_2)/(trianglel_1))^2=((10)/(2))^2`
`(U_2)/(U_1)=25`
`impliesU_2=25U_1`
So the correct choice is (b).