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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceDiagram basedEasyData or graph

JEE Main 4 August 2021, Shift 2, Physics Q15

Question 15 of 90 in this shift, Physics question 15 of 30, Section A.

Which is the correct graph to explain the Newton’s law of cooling. T and T0\mathrm{T_0} are the temperatures of hot body and surrounding respectively.

The figure, in words

All four options are graphs of log_e(T-T_0) against time; see options.
  1. (1)[figure: graph with vertical axis labelled log⁡e(T−T0)\log_e(T-T_0) and horizontal axis labelled time; a horizontal line above the time axis, with four dots marked on it]
  2. (2)[figure: graph with vertical axis labelled log⁡e(T−T0)\log_e(T-T_0) and horizontal axis labelled time; a straight line sloping downward from upper left to lower right, with four dots marked on it]Official answer
  3. (3)[figure: graph with vertical axis labelled log⁡e(T−T0)\log_e(T-T_0) and horizontal axis labelled time; a convex curve falling steeply at first and flattening towards a horizontal tail, above the time axis, with four dots marked on it]
  4. (4)[figure: graph with vertical axis labelled log⁡e(T−T0)\log_e(T-T_0) and horizontal axis labelled time; a straight line sloping upward, starting from a point on the time axis, with four dots marked on it]

Official answer

Option 2

NTA final key.

Chapter
Thermal Properties of Matter
Topic
Thermal Radiation
Idea tested
Logarithmic Graph of Newton's Law of Cooling

Same idea in other shifts

Asked 2× in all
  1. 24 Jun 2022, Shift 2 · Q60In an experiment to verify Newton’s law of cooling, a graph is plotted between, the temperature difference (Δ\DeltaT) of the water and…MediumNumerical valueHas a figure

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.