Two wires A and B are stretched by the same load . If the areas of cross - section of wire A is double that of B . then the stress in B is

Options

A. equal to that on A
B. twice that on A
C. half that on A
D. four times that on A

Answer

B

Explanation

As both wires A and B are stretched by the same load , (say W),
Stress on A is
`("stress")_A=W/A_A` and that on B is
`("stress")_B=W/A_B`
where `A_A and A_B` are the areas of cross - section of wires A and B respectively.
Thus, `(("stress")_B)/(("stress")_A)=A_A/A_B`
But as per equations `A_A = 2 A_B`
`:.(("stress")_B)/(("stress")_A)=2 " or "("stress")_B=2 ("stress")_A`