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A wire of length L, area of cross section A is hanging from a fixed support. The length of the wire changed to L1 when mass M is suspended from its free end. The expression for Young's modulus is :
(3) MgLA(L1 - L)
Stress = FA = MgA
Strain = LL = L1 - LL
Young's modulus Y = StressStrain
= Mg/A(L1 - L)/L
= MgLA(L1 - L)
Answer: (3)
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