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. What happens when a ship enters a Sea from a river ?
[A] It rises
[B] It remains at the same level
[C] sinks a little
[D] None of the above
Show Answer
Correct Answer: A [It rises]
Notes:
When a ship enters a sea from a river ,the ship is elevated or uplifted due to the density of sea water and during the buoyant motion of the ship, as it would gain both potential and kinetic energy when rising in the fluid.
2. Which of the following scientific discoveries was made by C.V Raman?
[A] Inelastic scattering of light by molecules
[B] Super Conductivity
[C] Controlled nuclear fission
[D] Cyclotron
Show Answer
Correct Answer: A [Inelastic scattering of light by molecules]
Notes:
C.V Raman discovered the Inelastic scattering of light by molecules in 1928, also named as ‘Raman effect’ Raman scattering is the inelastic scattering of a photon by molecules which are excited to higher vibrational or rotational energy levels. He was the first Indian Physicist to win the Nobel Prize for Physics in 1930. C.V Raman has also been bestowed with the Bharat Ratna Award.
3. 1 femto metre is equal to how many metres?
[A] 10-12
[B] 10-14
[C] 10-15
[D] 1-24
Show Answer
Correct Answer: C [ 10-15 ]
Notes:1 femto metre is equal to 10
-15 metre. Some other metric prefixes are:
- nano = 10-9
- pico = 10-12
- atto = 10-18
- tera = 1012
- peta = 10-15
- exa = 10-18
4. Which of the following is NOT correct about Vectors addition?
[A] Vectors addition is associative
[B] Vectors addition is commutative
[C] Vectors of different natures can be added
[D] None of the above
Show Answer
Correct Answer: C [Vectors of different natures can be added]
Notes:
Vectors addition is associative and commutative. But vectors of the same nature alone can be added. Example: a Force vector cannot be added to velocity vector as they are of different nature.
5. Which of the following is NOT correct about an inelastic collision?
[A] Linear momentum is conserved
[B] Kinetic energy is conserved
[C] Total energy is conserved
[D] Some or all the forces involved may be non-conservative in nature
Show Answer
Correct Answer: B [Kinetic energy is conserved]
Notes:
Following are the basic characteristics of an inelastic collision: 1. Linear momentum is conserved 2. Kinetic energy is NOT conserved 3. Total energy is conserved 4. Some or all the forces involved may be non-conservative in nature
6. On which of the following quantities, Work done does not depend?
[A] Force applied
[B] Displacement
[C] Time
[D] Depends on all of the above
Show Answer
Correct Answer: C [Time]
Notes:
Work done does not depend on the time for which the force was applied. Work done is only dependant on the force and displacement. Time is involved in the case of Power only
7. Which of the following is correct about the value of acceleration due to gravity?
[A] it is greater at mountains than in plains
[B] it is lesser at mountains than in plains
[C] it is equal for mountains and plains
[D] None of the above
Show Answer
Correct Answer: B [it is lesser at mountains than in plains]
Notes:
The value of acceleration due to gravity decreases with increase in height. Therefore, it is lesser at mountains than in plains.
8. What is the relation between the orbital velocity and the radius of the orbit for a given planet?
[A] greater the radius of orbit, lesser will be the orbital velocity
[B] greater the radius of orbit, greater will be the orbital velocity
[C] orbital velocity is independent of radius of orbit
[D] None of the above
Show Answer
Correct Answer: A [greater the radius of orbit, lesser will be the orbital velocity]
Notes:
For a given planet, greater the radius of orbit, lesser will be the orbital velocity of the satellite. The Orbital velocity depends on the mass of central body and radius of orbit.
9. 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.
10. What is Young’s Modulus?
[A] ratio of longitudinal strain to normal stress
[B] product of normal stress of longitudinal strain
[C] ratio of normal stress to longitudinal strain
[D] ratio of normal stress to lateral strain
Show Answer
Correct Answer: C [ratio of normal stress to longitudinal strain]
Notes:
Young’s Modulus is defined as the ratio of normal stress to longitudinal strain within limit of proportionality. Y = normal stress/longitudinal strain
