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 has highest velocity ?
[A] Hurricane
[B] Tornado
[C] Typhoon
[D] Cyclone
Show Answer
Correct Answer: B [Tornado]
Notes:
Tornadoes has the highest velocity and are more devastating compared to other types of cyclones. They generally occur in the pacific ocean.
2. When two mercury drops are brought into contact they form a single bigger drop to get which of the following?
[A] Minimum volume
[B] Minimum surface area
[C] Maximum size
[D] Maximum surface area
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Correct Answer: B [Minimum surface area]
Notes:
When two drops of mercury come into contact, they will tend to merge together and form a single drop with a minimum surface area. This is because of the properties of mercury, which is a liquid metal with a high surface tension. The surface tension of a liquid is a measure of its elasticity, and it is determined by the cohesive forces between the molecules of the liquid. In the case of mercury, the high surface tension causes the molecules at the surface of the liquid to be strongly attracted to each other, which results in the formation of a relatively smooth and spherical surface. When two drops of mercury are brought together, the surface tension causes them to merge and form a single drop with the smallest possible surface area. This phenomenon is known as the “minimization of surface area” and it is a common feature of liquids with high surface tension.
3. Which of the following waves is called compression-dilation waves or longitudinal waves?
[A] Primary waves
[B] Secondary waves
[C] Love waves
[D] Rayleigh waves
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Correct Answer: A [Primary waves]
Notes:
Primary wave is also called compression-dilation or longitudinal waves. Secondary wave is called transversal wave. Love wave and Rayleigh wave are surface waves. P waves can pass through solid, liquid and gases and are also the fastest among the three main types of waves.
4. When equal force acts for equal time on two masses, both gain:
[A] Same velocity
[B] Same acceleration
[C] Same kinetic energy
[D] Same momentum
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Correct Answer: D [Same momentum]
Notes:
When equal force acts for equal time, impulse (F × t) is equal. Impulse equals change in momentum, so both bodies gain same momentum regardless of their masses. Velocity and acceleration depend on mass, so they will differ.
5. Who among the following gave the Uncertainity principle?
[A] R.A Milkman
[B] Ernset Rutherford
[C] S.N Bose
[D] Werner Heisenberg
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Correct Answer: D [Werner Heisenberg]
Notes:
Werner Heisenberg, a german Physicist, discovered the Uncertainity principle. As per the uncertainty principle, we cannot measure the position (x) and the momentum (p) of a particle with absolute precision. The more accurately we know one of these values, the less accurately we know the other. It represnts the effects of wave-particle duality on the properties of subatomic objects.
6. What is the rate of acceleration produced by 1 dyne force acting on a body of mass 1 gram?
[A] 9.8 m s-2
[B] 1 m s-2
[C] 1 cm s-2
[D] 9.8 cm s-2
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Correct Answer: C [1 cm s-2]
Notes:
One dyne force is that much force which produces an acceleration of 1 cm s-2 in a body of mass one gram. 1 dyne = 1 g cm s-2 Also, 1 N = 105 dyne
7. Which of these is/are examples of conservation of linear momentum?
[A] Explosion of bomb
[B] Recoiling of a gun
[C] Fight of rockets and jet planes
[D] All of the above
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Correct Answer: D [All of the above]
Notes:Some examples of conservation of linear momentum:
- Recoiling of a gun
- Explosion of bomb
- Fight of rockets and jet planes
- A man jumping out of a boat to the shore
- A person on a frictionless surface
8. Which of the following is NOT a conservative force?
[A] Electrostatic force
[B] Magnetic force
[C] Force in an elastic spring
[D] Frictional force
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Correct Answer: D [Frictional force]
Notes:
A conservative force is a force with the property that the work done in moving a particle between two points is independent of the taken path. Examples: Electrostatic force, Magnetic force, Force in an elastic spring Frictional force is a non-conservative force.
9. At sea level, what is the difference between the value of acceleration due to gravity at the poles and at the equator?
[A] No difference
[B] 9.8 cm s-2
[C] 1.80 cm s-2
[D] None of the above
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Correct Answer: C [1.80 cm s-2]
Notes:
At sea level, the difference between the value of acceleration due to gravity at the poles and at the equator is 1.80 cm s-2. The value of acceleration due to gravity increases as we go from equator to the poles.
10. Which of the following has an effect on the value of acceleration due to gravity?
[A] Shape of the earth
[B] Height above the earth surface
[C] Axial rotation of the earth
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
The value of acceleration due to gravity vary due to the following factors : (a) Shape of the earth (b) Height above the earth surface (c) Depth below the earth surface (d) Axial rotation of the earth
