A rubber cord of length 40 cm and area of cross section 4 x 10−6 m2 is extended by 10 cm. If the energy gained is 20 joule , young's modulus of rubber is

Engineering

Physics

Physical Quantities

Acceleration

Stress Strain and Hookes Law New

Question

A rubber cord of length 40 cm and area of cross section 4 x 10⁻⁶ m² is extended by 10 cm. If the energy gained is 20 joule , young's modulus of rubber is

10⁸Nm⁻²

2 × 10⁸Nm⁻²

4 × 10⁸Nm⁻²

1.5 × 10⁶Nm⁻²

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$Energy = \frac{AY}{2 L} ℓ^{2}$
$20 = \frac{4 \times 10^{- 6} \times Y \times {(\frac{10}{100})}^{2}}{2 \times \frac{40}{100}}$
$Y = \frac{20 \times 2 \times 40}{4 \times 10^{- 6} \times {(\frac{10}{100})}^{2} \times 100}$

= 4 × 10⁸ N/m²