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Saturday, 31 October

JEE Main 2024 · PhysicsNumerical answerNumerical valueMediumMulti-step

JEE Main 31 January 2024, Shift 2, Physics Q53

Question 53 of 90 in this shift, Physics question 23 of 30, Section B.

Two blocks of mass 2 kg and 4 kg are connected by a metal wire going over a smooth pulley as shown in figure. The radius of wire is 4.0×10−54.0\times10^{-5} m and Young's modulus of the metal is 2.0×10112.0\times10^{11} N/m2^2. The longitudinal strain developed in the wire is 1απ\frac{1}{\alpha\pi}. The value of α\alpha is ________. [Use g=10g=10 m/s2^2]

The figure, in words

Wire over a fixed smooth pulley hanging from the ceiling; 2 kg block hangs on the left (higher), 4 kg block hangs on the right (lower).

Official answer

12

NTA final key.

Chapter
Mechanical Properties of Solids
Topic
Elasticity
Idea tested
Stress and Strain Types

Same idea in other shifts

Asked 8× in all
  1. 5 Apr 2024, Shift 2 · Q38Match List-I with List-II : List-I List-II (A) A force that restores an elastic body of unit area to its original state (I) Bulk modulus…EasyMatch the list
  2. 1 Feb 2024, Shift 2 · Q53One end of a metal wire is fixed to a ceiling and a load of 2 kg hangs from the other end. A similar wire is attached to the bottom of the…MediumNumerical value
  3. 30 Jan 2024, Shift 1 · Q37Young's modules of material of a wire of length 'L' and cross-sectional area A is Y. If the length of the wire is doubled and…EasySingle correct
  4. 30 Jan 2024, Shift 1 · Q53Each of three blocks P, Q and R shown in figure has a mass of 3 kg. Each of the wires A and B has cross-sectional area…HardNumerical valueHas a figure
  5. 6 Apr 2023, Shift 2 · Q53A metal block of mass m is suspended from a rigid support through a metal wire of diameter 14 mm. The tensile stress developed in the wire…EasyNumerical value
  6. 28 Jul 2022, Shift 2 · Q23A string of area of cross-section 4 mm24\ \mathrm{mm^2} and length 0.5 m is connected with a rigid body of mass 2 kg. The body is rotated in…MediumNumerical value
  7. 2 Apr 2017 (offline) · Q1A man grows into a giant such that his linear dimensions increase by a factor of 9. Assuming that his density remains same, the stress in…MediumSingle correct

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 108 of the 174 JEE Main shifts held from 2017 to 2026.