A steel wire of cross-section area 3 × 10^-6 m2 can withstand a maximum strain of 10^-3. Young’s modulus of steel is 2×10^11 N/m2. The maximum mass the wire can hold is

Q: A steel wire of cross-section area 3 × 10-6 m2 can withstand a maximum strain of 10-3 . Young’s modulus of steel is 2 × 1011 N/m2 . The maximum mass the wire can hold is (Take g = 10 m/s2)

(a) 40 kg

(b) 60 kg

(c) 80 kg

(d) 100 kg

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Ans: (b)
Sol: Young’s Modulus , $Y = \frac{Stress}{Strain}$

$Y = \frac{M g /A}{Strain}$

$M = \frac{Y A (Strain)}{g}$

$M = \frac{2 \times 10^{11} \times 3 \times 10^{-6} \times 10^{-3}}{10}$

M = 60 kg