A body of mass 3.14 kg is suspended from one end of a wire of length 10 m. The radius of cross-section of the wire is changing uniformly from 5 × 10^-4 m at the top (i.e. point of suspension) to 9.8 × 10^-4 m at the other end. Young’s modulus of the material of the wire is 2 × 10^11 Nm-2 . Then change in length of the wire is

Q: A body of mass 3.14 kg is suspended from one end of a wire of length 10 m. The radius of cross-section of the wire is changing uniformly from 5 × 10-4 m at the top (i.e. point of suspension) to 9.8 × 10-4 m at the other end. Young’s modulus of the material of the wire is 2 × 1011 N m-2 . Then change in length of the wire is

(a) 4 × 10-3 m

(b) 3 × 10-3 m

(c) 10-3 m

(d) 2 × 10-3 m

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Ans: (c)