JEE Advanced 2018 — Paper 2 — Question 10

A steel wire of diameter 0.5 mm and Young's modulus $2 \times 10^{11} \mathrm{Nm}^{-2}$ carries a load of mass M. The length of the wire with the load is 1.0 m . A vernier scale with 10 divisions is attached to the end of this wire. Next to the steel wire is a reference wire to which a main scale, of least count 1.0 mm , is attached. The 10 divisions of the vernier scale correspond to 9 divisions of the main scale. Initially, the zero of vernier scale coincides with the zero of main scale. If the load on the steel wire is increased by 1.2 kg , the vernier scale division which coincides with a main scale division is $\_\_\_\_$. Take $\mathrm{g}=10 \mathrm{~ms}^{-2}$ and is $\pi=3.2$.