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Saturday, 10 October

JEE Main 2024 · PhysicsNumerical answerNumerical valueHardMulti-step

JEE Main 6 April 2024, Shift 2, Physics Q60

Question 60 of 90 in this shift, Physics question 30 of 30, Section B.

A wire of cross sectional area AA, modulus of elasticity 2×1011 Nm−22\times10^{11}\ \mathrm{Nm^{-2}} and length 2 m is stretched between two vertical rigid supports. When a mass of 2 kg is suspended at the middle it sags lower from its original position making angle θ=1100\theta=\frac{1}{100} radian on the points of support. The value of AA is ________ ×10−4 m2\times10^{-4}\ \mathrm{m^2} (consider x≪Lx\ll L). (given : g=10 m/s2g=10\ \mathrm{m/s^2})

The figure, in words

Wire of total span 2L between two rigid vertical supports at the same level; a 2 kg mass hangs from the midpoint, which sags down by x; the wire makes angle theta with the horizontal at each support.

Official answer

1

NTA final key.

Chapter
Mechanical Properties of Solids
Topic
Elasticity
Idea tested
Hooke's Law

Same idea in other shifts

Asked 3× in all
  1. 6 Apr 2023, Shift 1 · Q58A steel rod has a radius of 20 mm and a length of 2.0 m. A force of 62.8 kN stretches it along its length. Young's modulus of steel is…EasyNumerical value
  2. 11 Apr 2023, Shift 1 · Q57The length of a wire becomes l1l_1 and l2l_2 when 100 N and 120 N tensions are applied respectively. If 10 l2=11 l110\,l_2 = 11\,l_1, the natural…MediumNumerical value

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.