NCERT  ·  Physics  ·  Ch.7

Gravitation

Universal Attraction · g on Earth · Satellites & Orbits

50
Questions
40 min
Duration
3
Tiers
6
Topics
⚡ Begin Analytics
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Question Intelligence

Quiz Analytics

A data-driven breakdown of all 50 questions by difficulty, exam origin and topic distribution.

📈 Distribution Overview

50
Total Questions
Concept Check (NCERT)
26
Boards / JEE Main
16
JEE/NEET Edge Cases
8

🗂 Topic Coverage

Universal Law & G
20%
g, Mass, Weight
20%
Earth, Moon & Planets
20%
Pressure & Thrust
16%
Buoyancy & Archimedes
16%
Floating, Sinking & Density
8%
26
Concept Check (NCERT)
16
Boards / JEE Main
8
JEE/NEET Edge Cases
Conceptual Framework

Key Concept Highlights

6 foundational pillars that power every question in this quiz. Understand these, and the answers follow naturally.

🌌
Universal Law of Gravitation
Every mass attracts every other mass with a force along the line joining them, proportional to the product of their masses and inversely proportional to the square of the distance.
🧲
G vs g
G is the universal gravitational constant that fixes the strength of gravity everywhere, while g is the local acceleration due to gravity on a particular planet or moon.
⚖️
Mass, Weight & Variation of g
Mass is the amount of matter and remains the same everywhere; weight is the gravitational force on a body and changes with the value of g on Earth, Moon and other planets.
🌍
Earth, Moon & Orbits
Gravitation keeps the Moon in orbit around Earth and planets around the Sun; the same law explains free fall, weightlessness and near-circular planetary paths.
💧
Pressure & Thrust in Fluids
Pressure in a liquid column depends on depth, density and gravitational acceleration, while thrust is the total normal force acting on a surface.
⚓
Buoyancy, Density & Archimedes
A body immersed in a fluid experiences an upward buoyant force equal to the weight of displaced fluid, which helps explain floating, sinking and relative density.
Pedagogical Value

Why MCQs Matter

Multiple-choice questions are not mere guessing games — they are the sharpest diagnostic tool available to a competitive exam aspirant.

~10–12%

of Class XI + XII Mechanics weightage across Boards & JEE/NEET (via gravitation, satellites & related numericals)

Quick Reference

Important Formula Capsules

8 must-memorise equations that surface repeatedly across CBSE and JEE papers.

Universal Law
\[ F = G \dfrac{m_1 m_2}{r^2} \]
Surface Gravity
\[ g = \dfrac{GM}{R^2} \]
Weight
\[ W = mg \]
Pressure (solid)
\[ P = \dfrac{F}{A} \]
Liquid Pressure
\[ P = h \rho g \]
Buoyant Force
\[ F_b = W_{\text{displaced fluid}} \]
Archimedes Principle
\[ F_b = \rho_{\text{fluid}} V_{\text{disp}} g \]
Density
\[ \rho = \dfrac{m}{V} \]
Learning Outcomes

What You Will Learn

By completing this quiz set you will have exercised all the following competencies.

01 State and apply the Universal Law of Gravitation to qualitative and numerical problems
02 Differentiate clearly between mass and weight and relate both to the value of g
03 Recall and use the approximate values of G, g, Earth’s mass and radius in calculations
04 Explain how g varies with altitude and why weight changes on the Moon and other planets
05 Compute pressure in solids and liquids using thrust, area, depth, density and g
06 Use Archimedes’ principle to decide when bodies float, sink or remain suspended in fluids
07 Interpret everyday situations like weightlessness, floating objects and planetary motion using gravitation concepts
Exam Preparation

Strategy & Preparation Tips

5 evidence-based strategies to maximise your score in CBSE Boards and JEE.

01
Step 01
Lock in the Core Statements
Memorise the exact statements of the Universal Law of Gravitation and Archimedes’ principle — CBSE and boards often ask them directly for short and long answers.
02
Step 02
Values & Units Drill
Practise quick recall of G, g, Earth’s mass and radius, and correct SI units for force, pressure, density and relative density to avoid easy unit-based mistakes.
03
Step 03
Mass vs Weight & g-Variation
Solve multiple questions comparing Earth vs Moon: which quantity changes, which remains constant, and how g varies with height or depth.
04
Step 04
Pressure & Buoyancy Numericals
Focus on hρg, thrust and buoyant force questions involving different liquids, depths and cross-sectional areas — they are standard and very scoring.
05
Step 05
Conceptual MCQs on Orbits
Revise why planets move in nearly elliptical orbits, what keeps the Moon around Earth, and how gravitational force changes with mass and distance for JEE/NEET-style MCQs.

Ready to Test Your Mastery?

50 questions  ·  Elapsed timer  ·  Instant scored results

⚡ Begin Gravitation Quiz
🎯 Knowledge Check

Physics — GRAVITATION

50 Questions Class 11 MCQs
1
The force of gravitation between two point masses is proportional to
2
The SI unit of gravitational constant \(G\) is
3
Gravitational force between two bodies becomes four times when the distance between them is
4
Acceleration due to gravity near the Earth’s surface depends on
5
The value of acceleration due to gravity is maximum at
6
Weight of a body is zero at
7
The gravitational potential energy at infinity is taken as
8
Gravitational potential energy of a body of mass \(m\) at distance \(r\) from Earth’s centre is
9
Escape speed from Earth depends on
10
Escape speed of Earth is approximately
11
A satellite revolves around Earth because
12
Orbital velocity of a satellite at height \(h\) is
13
Time period of a satellite in circular orbit varies as
14
Total energy of a satellite in circular orbit is
15
Gravitational force is always
16
Acceleration due to gravity inside Earth varies with depth \(d\) as
17
At what height above Earth’s surface will \(g\) become half of its value at surface?
18
Weightlessness in a satellite occurs because
19
Kepler’s second law is a consequence of conservation of
20
Which of the following has maximum escape speed?
21
Gravitational field intensity at Earth’s surface is numerically equal to
22
If Earth’s mass becomes double, escape speed becomes
23
The dimension of \(G\) is
24
A body projected with escape speed will reach infinity with
25
If distance between two masses is doubled, gravitational potential energy becomes
26
A satellite closer to Earth has
27
Gravitational force between Earth and Moon acts as
28
At the centre of Earth, gravitational potential energy is
29
If Earth stops rotating, value of \(g\) at equator will
30
For a satellite, increase in orbital radius leads to
31
A geostationary satellite has time period
32
The binding energy of a satellite is
33
If mass of Earth reduces to half, \(g\) becomes
34
Gravitational field inside Earth varies
35
At very large distances from Earth, gravitational potential tends to
36
Which quantity remains constant for a satellite in circular orbit?
37
The escape speed from Moon is smaller than Earth because Moon has
38
Gravitational force between two bodies does not depend on
39
A satellite moving in circular orbit has acceleration directed
40
If radius of Earth shrinks keeping mass constant, \(g\) will
41
For a satellite, doubling the orbital radius increases time period by factor
42
Weight of a body in a satellite is
43
Which law explains why planets sweep equal areas in equal times?
44
If orbital speed of a satellite is increased slightly, it will
45
The escape speed from a planet depends on
46
Gravitational potential at Earth’s surface is
47
A satellite in circular orbit has angular momentum
48
If a body is projected with speed less than escape speed, it will
49
Gravitational force provides centripetal force for
50
For Earth satellite motion, which quantity remains conserved?
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Frequently Asked Questions

Gravitation is the universal force of attraction acting between all bodies with mass, keeping objects grounded and governing planetary motion.

Every particle in the universe attracts every other particle with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them: \( F = G \frac{m_1 m_2}{r^2} \), where \( G = 6.67 \times 10^{-11} \, \mathrm{N \, m^2 \, kg^{-2}} \).

(1) Law of Orbits: Planets move in elliptical orbits with the Sun at one focus. (2) Law of Areas: The line from Sun to planet sweeps equal areas in equal times. (3) Law of Periods: \( T^2 \propto a^3 \), where \( T \) is orbital period and \( a \) is semi-major axis.

\( g = \frac{GM_E}{R_E^2} \approx 9.8 \, \mathrm{m/s^2} \), where \( M_E \) is Earth's mass and \( R_E \) is Earth's radius.

\( g_h = g \left(1 - \frac{2h}{R_E}\right) \) for \( h \ll R_E \); more generally \( g_h = \frac{GM_E}{(R_E + h)^2} \).

\( g_d = g \left(1 - \frac{d}{R_E}\right) \).

For two masses, \( U = -\frac{G m_1 m_2}{r} \) (zero at infinity).

Minimum speed to escape Earth's gravity: \( v_e = \sqrt{\frac{2GM_E}{R_E}} = \sqrt{2g R_E} \approx 11.2 \, \mathrm{km/s} \).

\( v_o = \sqrt{\frac{GM_E}{r}} \), where \( r = R_E + h \); relates to escape speed by \( v_e = \sqrt{2} v_o \).

Work done by gravity is path-independent, allowing definition of potential energy and conservation of mechanical energy in the gravitational field.

Force per unit mass: \( \vec{g} = -\frac{GM}{r^2} \hat{r} \); scalar potential \( V = -\frac{GM}{r} \).

Both satellite and occupants are in free fall toward Earth with the same acceleration, so no normal reaction is exerted on the body.

A satellite in circular equatorial orbit with time period \( T = 24 \,\text{h} \) at height \( h \approx 36{,}000 \,\text{km} \) that appears fixed over one point on Earth.

For a satellite very close to Earth’s surface, \( T_0 = 2\pi \sqrt{\frac{R_E}{g}} \approx 85 \,\text{min} \).

The gravitational force becomes \( \frac{1}{9} \) of the original, because \( F \propto \frac{1}{r^2} \).

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