A steel rod of length 1 m and radius 10 mm is stretched by a force 100 kN along its length. The stress produced in the rod is `Y_(Steel)=2xx10^(11)Nm^-2`

Options

A. `3.18 xx 10^(6) N m^(-2)`
B. `3.18 xx 10^(7) Nm^(-2)`
C. `3.18 xx 10^(8) N m^(-2)`
D. `3.18 xx 10^(9) N m^(-2)`

Answer

C

Explanation

Here r=2 cm `= 2 xx 10^(-2)m`
L=1m, F= 100 kN`= 100 xx 10^(-3) N = 10^(5) N`
Stress produced in the rod is
stress `=(F)/(A)= (F)/(pir^(2)) = (100 xx 10^(3)N)/(3.14 xx (10^(-2)m)^(2)) = 3.18 xx 10^(8) N m^(-2)`