Physics Circle home Student Login

Home›Chapters›Mechanical Properties of Solids PYQs›Young's Modulus & Elongation›Question 31

JEE Main 2009 (AIEEE) · Young's Modulus & Elongation

Young's Modulus & Elongation question from JEE Main 2009 (AIEEE)

Q31JEE Main 2009 · AIEEEMedium

Young's Modulus & Elongation

Two wires are made of the same material and have the same volume. However wire 11 has cross- sectional area AA and wire 22 has cross-sectional area 3A.3A. If the length of wire 11 increases by Δx\Delta x on applying force F,F, how much force is needed to stretch wire 22 by the same amount?

Show answer and solution

Answer: (c)

  1. Same volume: L=VAL = \frac{V}{A}, so F=YAΔxL=YA2ΔxV∝A2F = \frac{YA\Delta x}{L} = \frac{YA^2\Delta x}{V} \propto A^2 for the same Δx\Delta x.
  2. F2F=(3AA)2=9\frac{F_2}{F} = \left(\frac{3A}{A}\right)^2 = 9
  3. So the answer is (c) 9F9F.
Report a mistake

More questions on Young's Modulus & Elongation