General Science - Physics MCQs
Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examinations.
51. 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.
52. 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
53. Which of the following is equal to the upthrust of the body?
[A] mass of body
[B] weight of liquid
[C] weight of liquid displaced
[D] density of liquid
Show Answer
Correct Answer: C [weight of liquid displaced]
Notes:
Archimedes Principle: when a body is immersed partially or completely in a liquid, it experiences an upthrust, which is equal to the weight of the liquid displaced by the body.
54. What is the difference of pressure between two sides of the liquid surface called as?
[A] Excess Pressure
[B] Surface Pressure
[C] Fluidic Tension
[D] Viscosity
Show Answer
Correct Answer: A [Excess Pressure]
Notes:
In equilibrium the pressure inside a bubble or drop is more than the pressure outside. The difference of pressure between two sides of the liquid surface is called as excess pressure.
55. What is the density of water at 4°?
[A] 1.0
[B] 1.0 × 102 kg m–3
[C] 1.0 × 103 kg m–3
[D] 10 kg m–3
Show Answer
Correct Answer: C [ 1.0 × 103 kg m–3 ]
Notes:
The density of water at 4°C (277 K) is 1.0 × 103 kg m–3. The relative density of a substance is the ratio of its density to the density of water at 4° C.
56. What is the density of air at room temperature?
[A] 1.41
[B] 1.75
[C] 1.29
[D] 1.9
Show Answer
Correct Answer: C [ 1.29 ]
Notes:
The density of air at room temperature near the surface of the Earth is approximately 1.29 kg/m3.
57. What is the S.I unit of frequency?
[A] Second
[B] Watt
[C] Hertz
[D] Joule
Show Answer
Correct Answer: C [Hertz]
Notes:
The frequency is defined as the number of periodic motions executed by body per second. The S.I unit of frequency is hertz (Hz).
58. When are the two particles said to be in same phase?
[A] if the phase difference between them is an even multiple of π
[B] if the path difference is an even multiple of (λ / 2)
[C] if the time interval is an even multiple of (T/ 2)
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Two vibrating particle are said to be in same phase, if the phase difference between them is an even multiple of π or path difference is an even multiple of (λ / 2) or time interval is an even multiple of (T/ 2).
59. Which of these is correct about Simple Harmonic Motion?
[A] Restoring force is directly proportional to the displacement from mean position
[B] Restoring force is equal to the displacement from mean position
[C] Restoring force is inversely proportional to the displacement from mean position
[D] Restoring force is half of the displacement from mean position
Show Answer
Correct Answer: A [Restoring force is directly proportional to the displacement from mean position]
Notes:
Simple harmonic motion is a special type of periodic motion, in which a particle moves to and fro repeatedly about a mean position under a restoring force which is always directed towards the mean position and whose magnitude at any instant is directly proportional to the displacement of the particle from the mean position at that instant. Restoring force Displacement of the particle from mean position.
60. What are those oscillations whose amplitude goes on decreasing with time are known as?
[A] Damped oscillation
[B] Maintained oscillation
[C] Free oscillation
[D] Forced oscillation
Show Answer
Correct Answer: A [Damped oscillation]
Notes:
The oscillation of a body whose amplitude goes on decreasing with time are defined as damped oscillation. In these oscillation the amplitude of oscillation decreases exponentially due to damping forces like frictional force, viscous force, hystersis etc.
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