A copper wire was subjected to a tensile stress of 7.7 x 10
7 x 10 Nm
-2. calculate strain of the wire.
[young modules = 1.1 x 10
11 Nm
-2]
A. 2. 0 x 10
-5B. 7.0 x 10
-3C. 7.0 x 10
-4 
D. 2.2 x 10
-4 Correct Answer: C
Explanation
Young modules = \( \frac{\text{Tensile stress}}{\text{Tensile strain}}\)
= \( 1.1 \times 10^11 = \frac{7.7 \times 10^7}{\text{Tensile Strain}} \)
∴ Tensile strain = \( \frac{7.7 \times 10^7}{1.1 \times 10^11} \)
= \( 7.0 \times 10^{7-11}
= 7.0 \times 10^{-4} \)
