JEE 2020 Physics: Mechanical Properties of Solids Quiz 2 (14.08.2019) for JEE & BITSAT Exams

Question 1

In a wire stretched by hanging a weight from its end, the elastic potential energy per unit volume in terms of the longitudinal strain σ and modulus of elasticity Y is

Question 2

The length of a metal wire is L₁ when the tension is T₁ and L₂ when the tension is T₂. The unscratched length of the wire is

Question 3

Let L be the length and d be the diameter of cross section of a wire. Wires of the same material with different L and d are subjected to the same tension along the length of the wire. In which of the following cases, the extension of wire will be the maximum?

Question 4

A wire elongates by

mm when a load W is hanged from it. If the wire goes over a pulley and two weights W each are hung at the two ends, the elongation of the wire will be (in mm)

Question 5

Four rods

of the same material but the different radii

respectively held between two rigid walls. The temperature of all rods is increased through the same range. If the rods do not bend, then

Question 6

A pendulum made of a uniform wire of cross sectional area A has time period T. When an additional mass M is added to its bob, the time period changes to T_M. If Young’s modulus of the material of the wire is Y then

is equal to:
(g = gravitational acceleration )

Question 7

Two wires are made of the same material and have the same volume. However wire 1 has cross–section area A and wire 2 has cross–sectional area 3A. If the length of wire 1 increases by Δx on applying force F, how much force is needed to stretch wire 2 by the same amount?

Question 8

A metal wire of length L, area of cross section A and Young's modulus Y behaves as a spring constant k -

Question 9

A wire fixed at the upper end stretches by length λ by applying a force F. The work done in stretching is

Question 10

A wire of length L and radius r is fixed at one end. When a stretching force F is applied on the free end, the extension in the wire is η. Another wire of length 2L and radius 2r and of the same material is also fixed at one end. If a stretching force 2F is applied on the other end, then the elongation in the length of the wire will be -