Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, NDA, CDS and all one day examinations of India. These questions are part of GKToday’s 35000+ MCQs Bank Course in GKToday Android App
1. A pendulum is taken to Moon, what will happen to its time period?
[A] Increases
[B] Decreases
[C] Remains constant
[D] Either increase or decrease
Show Answer
Correct Answer: A [Increases]
Notes:
When the simple pendulum is taken to the moon, value of gravitational constant g will decrease and thus, its time period will increase.
2. How the brain interprets the frequency of an emitted sound is called its __:
[A] Pitch
[B] Amplitude
[C] Intensity
[D] Timbre
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Correct Answer: A [ Pitch]
Notes:
How the brain interprets the frequency of an emitted sound is called the pitch. Researchers have discovered a discrete region of the monkey brain that processes pitch, the relative high and low points of sound, by recognizing a single musical note played by different instruments.
3. 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.
4. Which of the following is correct about Kinetic energy during the projectile motion?
[A] it is minimum at the point of projection
[B] it is minimum at the highest point
[C] it is maximum at the highest point
[D] it is minimum at the point of reaching the ground
Show Answer
Correct Answer: B [it is minimum at the highest point]
Notes:
The Kinetic energy of an object is maximum at the point of projection or at the point of reaching the ground. It is minimum at the highest point.
5. The Universal Gravitational Constant for two bodies is dependent on which of the following?
[A] Nature of the bodies
[B] Size of the bodies
[C] Nature of medium between the bodies
[D] None of the above
Show Answer
Correct Answer: D [None of the above]
Notes:
The value of Universal Gravitational Constant is same throughout the universe. It is independent of nature of the bodies, size of the bodies and nature of medium between the bodies.
6. Which of the following is incorrect:
[A] Gravitational force of attraction is independent of nature of intervening medium
[B] Gravitational forces are central forces
[C] Gravitational forces are non-conservative forces
[D] All of the above
Show Answer
Correct Answer: C [Gravitational forces are non-conservative forces]
Notes:Characteristics of Gravitational Forces:
- It is always attractive in nature.
- It is independent of the medium between the bodies.
- It holds good over a wide range of distances
- It is a central force i.e. acts along the line joining the centres of two interacting bodies
- The gravitational force between two particles is independent of the presence or absence of other bodies
- It is the weakest force in nature.
- It is a conservative force i.e. work done by it is path independent or work done in moving a particle round a closed path under the action of gravitational force is zero.
- It is an action-reaction pair.
7. What is the SI unit of acceleration due to gravity?
[A] ms-2
[B] ms-3
[C] Kgms-2
[D] ms-1
Show Answer
Correct Answer: A [ms-2]
Notes:
The acceleration due to gravity is the acceleration set up in the body when it falls freely under the effect of gravity alone. The SI unit of acceleration due to gravity is ms-2
8. What is the dimensional formula of Gravitational Potential?
[A] M1 L2 T-2
[B] M1 L-2 T2
[C] M0 L2 T-2
[D] M0 L2 T2
Show Answer
Correct Answer: C [M0 L2 T-2]
Notes:
The dimensional formula of Gravitational Potential is M0 L2 T-2 It is a scalar quantity. S.I. units of Gravitational Potential is J/kg
9. On which of the following the gravitational force between two objects does not depend?
[A] Gravitational constant
[B] Distance between the objects
[C] Product of the masses of the objects
[D] Sum of the masses of the objects
Show Answer
Correct Answer: D [Sum of the masses of the objects]
Notes:
The gravitational force between two objects depends on the Gravitational constant, Distance between the objects and Product of the masses of the objects. F = Gravitational constant x (Product of the masses of the objects) / Square of Distance between the objects
10. What is the escape velocity of a planet having mass 6 times and radius 2 times as that of earth?
[A] 3 ve
[B] √2 ve
[C] √3 ve
[D] 2 ve
Show Answer
Correct Answer: C [√3 ve]
Notes:
Escape velocity of a satellite is given by ve = (2GM/r)1/2 So when M=6times and R=2R, then ve becomes √3 ve.
