A load of 20N on a wire of cross-sectional area 8 x 10-7m2, produces an extension of 10m2. calculate Young's modulus for the material of the wire if its length is 3m
A
7.0 x 1011Nm-2
B
7.5 x 1011Nm-2
C
8.5 x 1011Nm-2
D
9.0 x 1011Nm-2
Verified Correct Answer: B.
Physical Principles & Numerical Solution
Young's modulus = \(\frac{F}{A}\) \(\div\) \(\frac{e}{L}\)
= \(\frac{20}{8 \times 10^{-7}}\) \(\div\) \(\frac{10^{-4}}{3}\)
= 7.5 x 1011Nm-2
Source: Myschool Past Questions Archive (Record #27687)