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Saturday, 31 October

JEE Main 2025 · PhysicsMultiple choiceAssertion–reasonEasyConceptual

JEE Main 7 April 2025, Shift 2, Physics Q31

Question 31 of 75 in this shift, Physics question 6 of 25, Section A.

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : The radius vector from the Sun to a planet sweeps out equal areas in equal intervals of time and thus areal velocity of planet is constant. Reason (R) : For a central force field the angular momentum is a constant. In the light of the above statements, choose the most appropriate answer from the options given below :
  1. (1)Both (A) and (R) are correct and (R) is the correct explanation of (A)Official answer
  2. (2)Both (A) and (R) are correct but (R) is not the correct explanation of (A)
  3. (3)(A) is correct but (R) is not correct
  4. (4)(A) is not correct but (R) is correct

Official answer

Option 1

NTA final key.

Chapter
Gravitation
Topic
Orbital Mechanics
Idea tested
Areal Velocity and Angular Momentum

Same idea in other shifts

Asked 4× in all
  1. 26 Feb 2021, Shift 1 · Q3A planet revolving in elliptical orbit has : A. a constant velocity of revolution. B. has the least velocity when it is nearest to the…EasyOther
  2. 25 Jul 2021, Shift 1 · Q19The minimum and maximum distances of a planet revolving around the Sun are x1x_1 and x2x_2. If the minimum speed of the planet on its…EasySingle correct
  3. 18 Mar 2021, Shift 2 · Q10The angular momentum of a planet of mass M moving around the sun in an elliptical orbit is L⃗\vec{L}. The magnitude of the areal velocity…EasySingle 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.