JEE Main 2020 · PhysicsMultiple choiceSingle correctMediumMulti-step

JEE Main 2 September 2020, Shift 1, Physics Q6

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

The mass density of a spherical galaxy varies as

\frac{K}{r}

over a large distance 'r' from its centre. In that region, a small star is in a circular orbit of radius

R

. Then the period of revolution,

T

depends on

R

as :

(1) $T^{2}\propto R^{3}$
(2) $T^{2}\propto R$ Official answer
(3) $T\propto R$
(4) $T^{2}\propto\frac{1}{R^{3}}$

Official answer

Option 2

NTA final key (Sep 2020).

Chapter: Gravitation
Topic: Orbital Mechanics
Idea tested: Orbital Time Period

Same idea in other shifts

Asked 10× in all

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4 Apr 2024, Shift 2 · Q37Correct formula for height of a satellite from earths surface is:MediumSingle correct
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 $g = \pi^2$ m/s $^2$ , R = radius of…MediumSingle correct
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
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
24 Feb 2021, Shift 1 · Q5Consider two satellites $S_1$ and $S_2$ with periods of revolution 1 hr. and 8 hr. respectively revolving around a planet in circular…EasySingle correct
25 Feb 2021, Shift 1 · Q6Two 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 $T_A$ …MediumSingle correctHas a figure
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

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.