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JAMB Physics 2021 Paper

Question : 25

Total: 40

^{7}

^{-2}

Solution:

Concept:

Young's modulus measures how stiff a material is. It is the ratio of stress to strain.

Explanation:

Stress is

10^7 \, \text{N m}^{-2}

Original length is

l = 10.00 \, \text{m}

Final length is

10.05 \, \text{m}

Extension is

e = 10.05 - 10.00 = 0.05 \, \text{m}

Strain is

\frac{e}{l} = \frac{0.05}{10} = 0.005

Young's modulus is

\frac{\text{stress}}{\text{strain}}

E = \frac{10^7}{0.005} = 2.0 \times 10^9 \, \text{N m}^{-2}

Answer:

The Young's modulus of the wire is

2.0 \times 10^{9} \, \text{N m}^{-2}

, so the correct option is D.

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