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 is true about Total Internal Reflection?
[A] A ray passing from rarer to denser medium and not able to pass to denser medium at an angle greater than critical angle
[B] A ray passing from denser to rarer medium and not able to pass to rarer medium at an angle greater than critical angle
[C] A ray passing from either denser to rarer medium or rarer to denser medium and not able to pass any medium at an angle smaller than critical angle
[D] None of the above
Show Answer
Correct Answer: B [A ray passing from denser to rarer medium and not able to pass to rarer medium at an angle greater than critical angle]
Notes:
A ray passing from denser to rarer medium and not able to pass to rarer medium at an angle greater than critical angle. Critical angle is the angle in which the incident ray is 90 degrees to that of the refracted ray.
2. Which among the following is the most acceptable range of LEO (Low Earth orbit)?
[A] 350 – 2,600 kms
[B] 200-2000 kms
[C] 160 – 2,000 kms
[D] 160-1600 kms
Show Answer
Correct Answer: C [160 – 2,000 kms]
Notes:
This range is commonly used and accepted in the context of satellite orbits within the Earth’s atmosphere. It extends from approximately 160 kilometers (the Kármán line, which is often used as the boundary of space) to around 2,000 kilometers above the Earth’s surface.
3. “Svedberg Unit” is a measure of?
[A] Concentration
[B] Size
[C] Density
[D] Time
Show Answer
Correct Answer: D [Time]
Notes:
A Svedberg unit (S/ Sv) is utilized to denote sedimentation coefficients, providing specific measurement of a particle based on its sedimentation rate under acceleration. Essentially, it computes how quickly a particle settles to the bottom of a solution. In terms of the time dimension, a Svedberg unit amounts to exactly 10−13 seconds, indicating that it is essentially a measure of time.
4. Which among the following waves are used in the gemstone industry to change white topaz into blue topaz?
[A] X-Rays
[B] Gamma Rays
[C] Alpha Radiation
[D] Beta Radiation
Show Answer
Correct Answer: B [Gamma Rays]
Notes:
Gamma rays is commonly used in gemstone industry to change white topaz into blue topaz. Because white topaz is heat-treated to turn into blue topaz, the value of blue topaz is often decreased.
5. Who among the following is credited for the discovery of ‘Expanding Universe’?
[A] Edwin Hubble
[B] Niels Bohr
[C] S Chandra Shekhar
[D] C.V Raman
Show Answer
Correct Answer: A [Edwin Hubble]
Notes:
Edwin Hubble, an american astronomer, and was the first to prove that the universe is expanding. According to Expanding Universe theory, the universe is presently expanding. Hubble proved that there is a direct relationship between the speeds of distant galaxies and their distances from Earth. This is now known as Hubble’s Law.
6. What is the value of Triple point of water?
[A] 273.16 K
[B] 273.16° C
[C] 0° C
[D] -273.16 K
Show Answer
Correct Answer: A [ 273.16 K ]
Notes:
Triple point of water is the temperature at which ice, water and water vapours coexist. The value of Triple point of water is 273.16 K Kelvin is the S.I unit of Temperature represented by symbol K.
7. kg m2is the unit of which of the following physical quantities?
[A] Linear Momentum
[B] Angular Momentum
[C] Angular Impulse
[D] Moment of Inertia
Show Answer
Correct Answer: D [ Moment of Inertia ]
Notes:
kg m2is the unit of Moment of Inertia. The moment of inertia is a physical quantity which describes how easily a body can be rotated about a given axis. It is a rotational analogue of mass. Moment of Inertia = mass x (radius of gyration)2
8. 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.
9. The force acting on a body for a short time are called as:
[A] Average force
[B] Momentum
[C] Impulse
[D] Tension
Show Answer
Correct Answer: C [Impulse]
Notes:
The force acting on a body for a short time are called as Impulse. Example: hitting a ball with a bat. Impulse = average force x time It is a measure of total effect of the force. Its unit is Ns
10. The work done by a variable force is given by:
[A] area under the force curve and the displacement axis
[B] square of the area under the force curve and the displacement axis
[C] natural log of the area under the force curve and the displacement axis
[D] twice the area under the force curve and the displacement axis
Show Answer
Correct Answer: A [area under the force curve and the displacement axis]
Notes:
The work done by a variable force is given by the area under the force curve and the displacement axis. W = Area ABCDA
