A stress of `3.18 xx 10^(8) Nm^(-2)` is applied to a steel rod of length 1m along its length, its Young's modulus is `2 xx 10^(11) Nm^(-2)`. Then the elongation produced in the rod (in mm) is

Options

A. 3.18
B. 6.36
C. 5.18
D. 1.59

Answer

D

Explanation

As `Y = (F//A)/(Delta L//L) or (L (F//A))/(Y)`
Given, `(F)/(A)`= stress `=3.18 xx 10^(8) Nm^(-2), L= 1m, Y = 2 xx 10^(11) Nm^(-2)`
`:. Delta L = (L (F//A))/(Y) = (1xx 3.18 xx 10^(8))/(2 xx 10^(11)) = 1.59 xx 10^(-3) m= 1.59mm`