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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 25 February 2021, Shift 1, Physics Q6

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

Two satellites A and B of masses 200 kg and 400 kg are revolving round the earth at height of 600 km and 1600 km respectively. If TAT_A and TBT_B are the time periods of A and B respectively then the value of TB−TAT_B - T_A : [ Given : radius of earth = 6400 km, mass of earth = 6×10246\times10^{24} kg ]

The figure, in words

Two concentric circular orbits around a small circle with a dot labelled E at the centre; the inner orbit has a point labelled A on it and the outer orbit has a point labelled B on it.
  1. (1)1.33×1031.33\times10^{3} sOfficial answer
  2. (2)4.24×1034.24\times10^{3} s
  3. (3)4.24×1024.24\times10^{2} s
  4. (4)3.33×1023.33\times10^{2} s

Official answer

Option 1

NTA final key.

Chapter
Gravitation
Topic
Orbital Mechanics
Idea tested
Orbital Time Period

Same idea in other shifts

Asked 10× in all
  1. 2 Apr 2026, Shift 1 · Q30A planet (P1P_1) is moving around the star of mass 2M2M in the orbit of radius RR. Another planet (P2P_2) is moving around another star…EasySingle correct
  2. 4 Apr 2024, Shift 2 · Q37Correct formula for height of a satellite from earths surface is:MediumSingle correct
  3. 10 Apr 2023, Shift 2 · Q37The time period of a satellite, revolving above earth's surface at a height equal to R will be (Given g=π2g = \pi^2 m/s2^2, R = radius of…MediumSingle correct
  4. 29 Jun 2022, Shift 2 · Q40The time period of a satellite revolving around earth in a given orbit is 7 hours. If the radius of orbit is increased to three times its…EasySingle correct
  5. 3 Aug 2021, Shift 1 · Q28The time period of a satellite of earth is 10 hours. If the separation between the earth and the satellite is increased to 16 times the…EasyNumerical value
  6. 24 Feb 2021, Shift 1 · Q5Consider two satellites S1S_1 and S2S_2 with periods of revolution 1 hr. and 8 hr. respectively revolving around a planet in circular…EasySingle correct
  7. 17 Mar 2021, Shift 2 · Q4A geostationary satellite is orbiting around an arbitary planet 'P' at a height of 11R above the surface of 'P', R being the radius of…EasySingle correct
  8. 18 Mar 2021, Shift 2 · Q5If the angular velocity of earth’s spin is increased such that the bodies at the equator start floating, the duration of the day would be…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.