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 of the following statements is incorrect about a Plane Mirror?
[A] The focal length of a plane mirror is infinity
[B] Its optical power is one
[C] It forms a virtual image of a real object
[D] It is used in constructing periscope
Show Answer
Correct Answer: B [Its optical power is one]
Notes:
Second statement is incorrect because the optical power of plane mirror is zero.
2. Which among the following is true about latent heat ?
[A] It causes change in temperature as well as change in state or phase
[B] It causes change in temperature only
[C] It causes change in state or phase but not in temperature
[D] It causes change in Pressure
Show Answer
Correct Answer: C [It causes change in state or phase but not in temperature]
Notes:
The latent heat Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. It causes change in state or phase but not in temperature.
3. Which among the following Radio frequencies are used around the world in air navigational system?
[A] Very Low Frequency (VLF)
[B] Very High Frequency (VHF)
[C] Tetrahertz Radiation (THF)
[D] Ultra High Frequency (UHF)
Show Answer
Correct Answer: B [ Very High Frequency (VHF)]
Notes:
VHF (Very High Frequency) omnidirectional radio range (VOR), is a short-range radio navigation system for aircraft, enabling aircraft to determine their position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons, with a receiver unit. Uses radio frequencies in the very high frequency (VHF) band from 108 to 117.95 MHz. VOR is the standard air navigational system in the world, used by both commercial and general aviation.
4. We can hear a whooshing sound when we hold a spiral conch shell near our ears. What is the most likely reason behind this?
[A] The sound we hear is echoing of our blood rushing through the blood vessels of our ear
[B] The sound is generated by air flowing through the shell – in and out
[C] The ambient noise around us resonates inside the shell
[D] None of the reasons mentioned in statements A, B or C is correct
Show Answer
Correct Answer: C [ The ambient noise around us resonates inside the shell]
Notes:
The most likely explanation for the wave-like noise is ambient noise from around us. The seashell that we hold just slightly above our ear captures this noise, which resonates inside the shell.
5. Who among the following is credited to work for the unification of electricity, magnetism and optics field of Physics?
[A] James Clerk Maxwell
[B] Michael Faraday
[C] Haris Christian Oersted
[D] Isaac Newton
Show Answer
Correct Answer: A [James Clerk Maxwell]
Notes:
James Clerk Maxwell made the efforts for the unification of electricity, magnetism and optics field of Physics. He showed that light is an electromagnetic wave. James Clerk Maxwell was a Scottish mathematician, physicist and is known best for his mathematical work on electromagnetism and on the behaviour of gases.
6. What is the work done by centripetal force in case of Uniform Circular Motion?
[A] 1 joule
[B] 0 joule
[C] Depends on the magnitude of Force
[D] None of the above
Show Answer
Correct Answer: B [0 joule]
Notes:
The work done by Centripetal Force in case of Uniform Circular Motion is zero. The displacement and force are mutually perpendicular to each other in case of centripetal force. Therefore the work done is zero.
7. Which of the following statements is correct?
[A] The acceleration due to gravity is same at the equator and the poles
[B] The acceleration due to gravity is maximum at the poles
[C] The acceleration due to gravity is least at the poles
[D] None of the above
Show Answer
Correct Answer: B [The acceleration due to gravity is maximum at the poles]
Notes:
The acceleration due to gravity is maximum at the poles and is least at the equator. The value of acceleration due to gravity increases as we go from the equator to the pole.
8. What is the dimensional formula of Stress?
[A] M 1 L-2 T-2
[B] M 1 L-1 T-1
[C] M 1 L1 T-3
[D] M 1 L-1 T-2
Show Answer
Correct Answer: D [M 1 L-1 T-2]
Notes:
Stress is defined as external force per unit area on a body that tends to cause it to deform. The dimensional formula of Stress is M 1 L-1 T-2
9. 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
10. What is the upward force experienced by a body, when it is immersed in a fluid, known as?
[A] Tangential force
[B] Buoyant force
[C] Centrifugal force
[D] Hydraulic force
Show Answer
Correct Answer: B [Buoyant force]
Notes:
When a body is immersed in a fluid (liquid or gas) it exerts an upward force on that body. This upward force is called up thrust or buoyant force, The whole phenomenon is called as buoyancy.
