Find the Young's modulus of the wire whose stress-strain curve is as shown in the following figure

• A

  $8 \times 10^{11} \mathrm{Nm}^{-2}$
• B

  $24 \times 10^{11} \mathrm{Nm}^{-2}$
• C

  $10 \times 10^{11} \mathrm{Nm}^{-2}$
• Correct answer
  D

  $2 \times 10^{11} \mathrm{Nm}^{-2}$

Solution

We know that, stress $=Y \times$ strain (Under proportional limit)
Now Young's modulus, $Y=\frac{\text { Stress }}{\text { Strain }}=\frac{(8-0) \times 10^7}{(4-0) \times 10^{-4}}$ $=2 \times 10^{11} \mathrm{Nm}^{-2}$

Hence, the correct answer is option: 'D'.