JEE Advanced2018PhysicsMechanical Properties of SolidsActual
A steel wire of diameter 0.5 m m and Young's modulus 2 × 10 11 N m - 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,
Correct answer
0
Step-by-step solution
d = 0.5   m m Y = 2 × 10 11 l = 1 m ∆ l = F l A y = m g l π d 2 4 y = 1.2 × 10 × 1 π 4 × 5 × 10 - 4 2 × 2 × 10 11 ∆ l = 1.2 × 10 3.2 4 × 25 × 10 - 8 × 2 × 10 11 =   12 1.6 × 25 × 10 3 = 12 40 × 10 3 = 0.03 m m So 3 rd division of vernier scale will coincicle with main scale