Question

Wires `A` and `B` are made from the same material. `A` has twice the diameter and three times the length of `B`. If the elastic limits are not reached, when each is stretched by the same tension, the ratio of energy stored in `A` to that in `B` is
A. `2:3`
B. `3:4`
C. `3:2`
D. `6:1`

Answer 1

Correct Answer - B
`U=(1)/(2)Fl=(F^2L)/(2AY).Uprop(L)/(r^2)`
`(U_A)/(U_B)=((L_A)/(L_B))xx((r_A)/(r_B))^2=(3)xx((1)/(2))^2=(3)/(4)`