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 principle is used by Bats?
[A] RADAR (Radio Detective & Ranging
[B] SONAR (Sound Navigation & Ranging
[C] law of reflection
[D] law of diffraction
Show Answer
Correct Answer: B [SONAR (Sound Navigation & Ranging]
Notes:
Bats use SONAR (Sound Navigation & Ranging).Sonar is a technique that uses sound propagation to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels.
2. Which among the following waves are most commonly used in the Night Vision Devices?
[A] Microwaves
[B] Infra Red Waves
[C] Ultra Violet Waves
[D] Radio Waves
Show Answer
Correct Answer: B [Infra Red Waves]
Notes:
Infrared waves are used in the night vision apparatus such as night vision goggles. Active infrared night-vision combines infrared illumination of spectral range 700–1,000 nm (just below the visible spectrum of the human eye) with CCD cameras sensitive to this light.
3. Who among the following is credited for the Corpuscular theory of light?
[A] Isaac Newton
[B] Christiaan Hyugens
[C] Albert Einstein
[D] James Clerk Maxwell
Show Answer
Correct Answer: A [Isaac Newton]
Notes:
The Corpuscular theory of light was given by Isaac Newton. It was replaced by Huygens’ wave theory when it failed to adequately explain the diffraction, interference and polarization of light. The Huygens’ wave theory was replaced by Planck’s quantum theory and finally de-Broglie’s Dual-Theory of light replaced all previous ones.
4. Which of the following is correct about the properties of Gravitational Forces?
[A] They are the strongest forces in nature
[B] They observe inverse square law
[C] Both a and b
[D] None
Show Answer
Correct Answer: B [They observe inverse square law]
Notes:
Gravitational Forces are the weakest forces in nature. They obey inverse square law as they vary inversely as the square of the distance between the two bodies. They are central forces and conservative forces. They operate over very long distances having an infinite range.
5. What is the S.I. unit for Luminous Intensity?
[A] mole
[B] ampere
[C] candela
[D] weber
Show Answer
Correct Answer: C [ candela ]
Notes:
The S.I. unit for Luminous Intensity is candela. The symbol used for candela is cd. Mole is the S.I unit for Quantity of Matter ampere is the S.I unit for Electric Current. Weber is the S.I unit for Magnetic Flux Luminous Intensity is the amount of light that a point source radiates in a given direction
6. What is represented by the slope of a straight line joining two points on a velocity-time graph?
[A] Average velocity
[B] Instantaneous acceleration
[C] Average acceleration
[D] None of the above
Show Answer
Correct Answer: C [Average acceleration]
Notes:
The slope of a straight line joining two points on a velocity-time graph gives the average acceleration between these two points. Depending on the sign of slope, the average acceleration can be positive or negative.
7. Two vectors are said to be equal if:
[A] they have equal magnitude and same direction
[B] they have equal magnitude and opposite direction
[C] they have equal magnitude and common initial point
[D] they have equal magnitude irrespective of the direction
Show Answer
Correct Answer: A [they have equal magnitude and same direction]
Notes:
Two vectors are said to be equal if they have equal magnitude and same direction. Two vectors are said to be co-initial if their initial point is common.
8. The thrust on the rocket is:
[A] in the same direction of the rocket
[B] in the opposite direction of the rocket
[C] at 90° to the direction of the rocket
[D] None of the above
Show Answer
Correct Answer: B [in the opposite direction of the rocket]
Notes:
The thrust on the rocket is in the opposite direction of the rocket. The thrust is the force with which rocket moves upwards. F = -u (dm/dt)
9. 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
10. Which of the following represents the dimensional formula of Universal Gravitational Constant?
[A] M1 L2 T-2
[B] M-1 L1 T-2
[C] M-1 L3 T-2
[D] M1 L3 T-2
Show Answer
Correct Answer: C [M-1 L3 T-2]
Notes:
The dimensional formula of Universal Gravitational Constant is M-1 L3 T-2 Universal Gravitational Constant is a scalar quantity.
