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

Question

A rubber cord of length 40cm and area of cross section 4 × 10-6 m2 is extended by 10cm. If the energy gained is 20 joule, (young's modulus of rubber is (A) 108 Nm-2 (B) 2 × 108 Nm-2 (C) 4 × 108 Nm-2 (D) 1.5 × 108 Nm-2

Tardigrade Admin · Accepted Answer

Energy =( AY /2 L ) l 2 20=(4 × 10-6 × Y ×((10/100))2/2 × (40)100) Y =(20 × 2 × 40/4 × 10-6 ×((10)100)2 × 100) =4 × 108 N / m 2

Q. A rubber cord of length 40cm and area of cross section $4 \times 1 0^{- 6} m^{2}$ is extended by 10cm. If the energy gained is 20 joule, (young's modulus of rubber is

$1 0^{8} N m^{- 2}$

$2 \times 1 0^{8} N m^{- 2}$

$4 \times 1 0^{8} N m^{- 2}$

$1.5 \times 1 0^{8} N m^{- 2}$

Energy $= \frac{A Y}{2 L} l^{2}$
$20 = \frac{4 \times 1 0 ^{- 6} \times Y \times ( \frac{10}{100} ) ^{2}}{2 \times \frac{40}{100}}$
$Y = \frac{20 \times 2 \times 40}{4 \times 1 0 ^{- 6} \times ( \frac{10}{100} ) ^{2} \times 100}$
$= 4 \times 1 0^{8} N / m^{2}$

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

108Nm−2

2×108Nm−2

4×108Nm−2

1.5×108Nm−2