Longitudinal stress of `1 kg//mm^(2)` is applied on a wire. The percentage increase in length is `(Y = 10^(11) N//m^(2))`

Options

A. 0.002
B. 0.001
C. 0.003
D. 0.01

Answer

B

Explanation

From hooke.s law
Stress `prop` Strain
From the question given that stress
`= 1kg//mm^(2)`
`rArr 1 kg//10^(-6) m^(2)`
`rArr 10^(6) kg//m^(2)`
Young.s modulus `Y = 10^(11) N//m^(2)`
`(DeltaL)/L xx 100 = ?`
Stress =`10^(6) xx 9.8 N//m^(2)`
`[therefore (1 kg)/m = 1 xx 9.8 N//m^(2)]`
Strain = `("stress")/Y`
strain is change in length upon orignal length
`(DeltaL)/L rArr (9.8 xx 10^(6))/10^(11)`
`rArr 10 xx 10^(-5) xx 100`
`rArr 10^(-2)`
`[therefore 9.8 ~= 10]`
`(DeltaL)/L xx 100 = 0.01`