Two wires are made of the same material an have the same volume, However wire 1 has cross sectional area `2A` and wire 2 has cross- sectional area `4A`. If the length of wire 1 increases by `Deltax` on applying foce F, how much force is needed to stretch wire 2 by the same amount ?

Options

A. 4F
B. 3F
C. 2F
D. F

Answer

A

Explanation

`(F)/(2A) = Y (Deltax)/(l) rArr 2AY (Deltax)/(l)`
`(F')/(4A) = Y (Deltax)/((l)/(2)) rArr F' = 8 Y (Delta x)/(l) A = 4F`