90. A steel wire of lm long and cross section area is

A steel wire of lm long and cross section area is 1mm² hang from rigid end. When weight of 1kg is hung from it then change in length will be (given Y=2×10¹¹N/m²)

(a)   0.5 mm                                   (b)   0.25 mm

(c)   0.05 mm                                 (d)   5 mm

Answer-c

(4)