Physics MCQs
Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, NDA, CDS and all one day examinations of India.
1. Which among the following defines gravitational mass?
[A] Ratio of weight of a body and acceleration due to gravity
[B] Ratio of Acceleration due to gravity and weight of a body
[C] matter contained in a body
[D] None of the above
Show Answer
Correct Answer: A [Ratio of weight of a body and acceleration due to gravity]
Notes:
Gravitational mass is the Ratio of weight of a body and acceleration due to gravity. Gravitational mass is the mass of a body as measured by its gravitational attraction for other bodies.
2. The value of acceleration due to gravity is __________?
[A] Minimum at equator and maximum at poles
[B] maximum at equator and minimum at poles
[C] equal at poles and equator
[D] None of the above
Show Answer
Correct Answer: A [Minimum at equator and maximum at poles]
Notes:
The value of acceleration due to gravity is maximum at equator. This is because the distance from the center is minimum at the equator.
3. At which of the following places water shall boil at the lowest temperature?
[A] Kochi
[B] Ooty
[C] Mount Abu
[D] New Delhi
Show Answer
Correct Answer: B [Ooty]
Notes:
This question is related to Antoine equation. Water to get boil, its vapour pressure must reach to its surrounding pressure. In a pressure cooker, it boils at the highest temperature. Elevation of Kochi is 0 m, ooty is 2,486 m, Mount Abu is 1,200 m, New Delhi is 216 m, Shimla is 2,205 m. So comparing all of them, water will boil at lowest temperature at ooty, followed by Shimla, Mount Abu , New Delhi and Kochi. This is because , higher we go lower is the atmospheric pressure and lower is the point where water`s vapour pressure gets equal to the atmospheric pressure.
4. What is the force of attraction between any two bodies by virtue of their masses is called?
[A] Electromagnetic Force
[B] Gravitational Force
[C] Centripetal Force
[D] Nuclear Force
Show Answer
Correct Answer: B [Gravitational Force]
Notes:
Gravitational Force is the force of attraction between any two bodies by virtue of their masses. It is a universal force and every object in the universe experiences gravitational force due to every other object.
5. Which of the following conditions is true for an object to be in equilibrium?
[A] No linear motion of the object
[B] No rotational motion of the object
[C] Minimum potential energy of the object
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
The conditions for equilibrium for an object: 1. There is no linear motion of the object i.e. the resultant force on the object is zero 2. There should not be any rotational motion of the object i.e. the torque on the object should be zero 3. The potential energy of the object should be minimum for stable equilibrium.
6. The work done in moving a body over a smooth inclined plane does not depend on which of the following?
[A] mass of the body
[B] height of the inclined plane
[C] slope of the inclined plane
[D] All of the above
Show Answer
Correct Answer: C [slope of the inclined plane]
Notes:
The work done in moving a body over a smooth inclined plane does not depend on the slope of the inclined plane. W = mgh in case of smooth inclined plane, where m = mass of the body, g = acceleration due to gravity and h = height of the inclined plane.
7. Which of these represent the Angular momentum of a satellite?
[A] mvr
[B] ma
[C] mr
[D] mvh
Show Answer
Correct Answer: A [mvr]
Notes:
Angular momentum of satellite is given by mvr. Angular momentum of satellite depend on both the mass of orbiting and central body as well as the radius of orbit.
8. What is the order of distance for Vander Wall forces to be active?
[A] 10–6 metre
[B] 10–7 metre
[C] 10–8 metre
[D] 10–9 metre
Show Answer
Correct Answer: D [10–9 metre]
Notes:
The forces between the molecules because of the electrostatic interaction between the charges of the molecules are called intermolecular forces. These forces are also called Vander Waal forces. They are quite weak as compared to inter-atomic forces. These forces are also electrical in nature. They are active if the separation between two molecules is of the order of molecular size i.e. 10–9 metre.
9. What happens to a body when its density is greater than the density of the fluid?
[A] it floats
[B] it sinks
[C] it stays at rest
[D] None of the above
Show Answer
Correct Answer: B [it sinks]
Notes:
The body sinks in the fluid in case its density is greater than the density of the fluid. For example, an iron nail has greater density than water, therefore it sinks in water.
10. Which of the following is NOT an application of principle of floatation?
[A] Ships
[B] Balloons
[C] Submarines
[D] None of the above
Show Answer
Correct Answer: D [None of the above]
Notes:
The principle of floatation states that a floating object displaces its own weight of the fluid in which it floats. Some of the applications of the principle of Floatation:- 1. Ships 2. Balloons 3. Submarines
