If the given graph shows the load $(\mathrm{W})$ attached to and the elongation $(\Delta l)$ produced in a wire of length one meter and area of cross-section $1 \mathrm{~mm}^2$, then the Young's modulus of the material of the wire is

• A

  $20 \times 10^{10} \mathrm{~N} \mathrm{~m}^{-2}$
• Correct answer
  B

  $2 \times 10^{10} \mathrm{~N} \mathrm{~m}^{-2}$
• C

  $10 \times 10^{10} \mathrm{~N} \mathrm{~m}^{-2}$
• D

  $4 \times 10^{10} \mathrm{~N} \mathrm{~m}^{-2}$

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