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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 24 February 2021, Shift 1, Physics Q6

Question 6 of 90 in this shift, Physics question 6 of 30, Section A.

Each side of a box made of metal sheet in cubic shape is ‘a’ at room temperature ‘T’, the coefficient of linear expansion of the metal sheet is ‘α\alpha’. The metal sheet is heated uniformly, by a small temperature Δ\DeltaT, so that its new temperature is T+Δ+\DeltaT. Calculate the increase in the volume of the metal box.
  1. (1)4πa3αΔT4\pi a^{3}\alpha\Delta T
  2. (2)4a3αΔT4a^{3}\alpha\Delta T
  3. (3)43πa3αΔT\frac{4}{3}\pi a^{3}\alpha\Delta T
  4. (4)3a3αΔT3a^{3}\alpha\Delta TOfficial answer

Official answer

Option 4

NTA final key.

Idea tested
Volume Expansion

Same idea in other shifts

Asked 2× in all
  1. 25 Jun 2022, Shift 2 · Q34A solid metallic cube having total surface area 24 m224\ \mathrm{m}^2 is uniformly heated. If its temperature is increased by…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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.