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. Any moving object on earth finally comes to rest due to which among the following?
[A] Gravity
[B] Friction
[C] Inertia
[D] Motion
Show Answer
Correct Answer: B [Friction]
Notes:
Friction is the main reason for any object to come to rest. It is the main reason for the stability of the objects on earth.
2. When a tubelight breaks, a cracking sound is produced because ____?
[A] Pressure inside the lamp is less than atmospheric pressure
[B] Pressure inside the lamp is more than atmospheric pressure
[C] The lamp is filled with reactive gases
[D] The lamp is filled with mercury vapour
Show Answer
Correct Answer: A [Pressure inside the lamp is less than atmospheric pressure ]
Notes:
A fluorescent lamp tube is filled with a gas containing low pressure mercury vapor and argon, xenon, neon, or krypton. The pressure inside the lamp is around 0.3% of atmospheric pressure.
3. A transition from the solid to gas phase with no intermediate liquid stage is called?
[A] Evaporation
[B] Sublimation
[C] Adsorption
[D] Solid Phase extraction
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Correct Answer: B [Sublimation]
Notes:
Sublimation is the process by which a substance transitions from a solid to a gas without passing through a liquid phase. This typically occurs when a substance is heated to a temperature at which its solid form becomes a gas, such as when dry ice (solid carbon dioxide) sublimates and turns into gas. Sublimation can also occur when a substance is exposed to a vacuum, which can cause gases to be drawn out of the substance and turn into a solid. Sublimation is an important process in many scientific and industrial fields, including meteorology, chemistry, and materials science. Camphor is also an example of Sublimation.
4. A person is standing in front of a wall and makes a sound. What should be the normal minimum distance between the person and the wall , so that the person hears echo?
[A] 6 meters
[B] 13 meters
[C] 20 meters
[D] 17 meters
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Correct Answer: D [17 meters]
Notes:
To hear an echo, the minimum distance between a wall and the source of sound is 17m. The minimum interval is 0.1 sec.
5. What is the range of masses involved in the study of Physics?
[A] 10-19 kg to 1038 kg
[B] 10-30 kg to 1055kg
[C] 10-30 kg to 1030kg
[D] 10-19 kg to 1055 kg
Show Answer
Correct Answer: B [10-30 kg to 1055kg]
Notes:
The range of masses involved in the study of Physics ranges from 10-30 kg to 1055 kg. 10-30kg is the mass of an electron and 1055 kg is the mass of known observable universe. The range of time scale involved in the study of Physics ranges from 10-22 s to 1018 s. The range of length involved in the study of Physics ranges from 10-14m to 1026 m.
6. Joule/kg is the S.I unit of which of these physical quantities?
[A] Entropy
[B] Permittivity of free space
[C] Latent heat
[D] Gas constant
Show Answer
Correct Answer: C [ Latent heat ]
Notes:
Joule/kg is the S.I unit of Latent heat Latent heat(L) = heat(Q)/mass(m) Latent heat is the heat required to convert a solid into a liquid or vapor, or a liquid into a vapor, without any change in temperature. Unit of Entropy: J/K Unit of Permittivity of free space: H/m Unit of Gas constant : J/K
7. Which of these pairs has the same unit of measurement?
[A] Rate of flow and Acceleration
[B] Impulse and Moment of Force
[C] Rydberg constant and Gas constant
[D] Pressure and Coefficient of Elasticity
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Correct Answer: D [ Pressure and Coefficient of Elasticity ]
Notes:
Pressure and Coefficient of Elasticity have the same unit i.e. N m-2 (Newton per metre square) Other important units: Rate of Flow: m3s-1 Acceleration: ms-2 Rydberg constant: 1/m Gas constant: J/K Impulse: Ns Moment of Force: Nm
8. What is the rate of acceleration produced by 1 dyne force acting on a body of mass 1 gram?
[A] 9.8 m s-2
[B] 1 m s-2
[C] 1 cm s-2
[D] 9.8 cm s-2
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Correct Answer: C [1 cm s-2]
Notes:
One dyne force is that much force which produces an acceleration of 1 cm s-2 in a body of mass one gram. 1 dyne = 1 g cm s-2 Also, 1 N = 105 dyne
9. 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
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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
10. What is the maximum stress after which the wire breaks called as?
[A] Tensile strength
[B] Shear strength
[C] Bulk strength
[D] Hooke’s strength
Show Answer
Correct Answer: A [Tensile strength]
Notes:
The maximum stress after which the wire begin to flow and breaks, is called breaking stress or tensile strength. The force by application of which the wire breaks is called the breaking force.
