A and B are two wire. The radius of A is twice that of B. If they are stretched by the same load, then the stress on B is

Options

A. four times that of A.
B. two times that of A.
C. three times that of A.
D. same as that of A.

Answer

A

Explanation

Four times that of A.
`("Stress on B")/("Stress of A") = (r_(A)^(2))/(r_(B)^(2))`
`rArr ("Stress on B")/("Stress of A") = ((2r_(B))^(2))/(r_(B)^(2)) ( :' r_(A) = 2r_(B))`
`:. ("Stress on B")/("Stress of A") = 4`
Stress on B `= 4 xx "Stress on A"`