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. Speed of sound is maximum in which among the following?
[A] Solids
[B] liquids
[C] Gases
[D] Vaccum
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Correct Answer: A [Solids]
Notes:
The speed of sound decreases when we go from solid to gaseous state.
2. In context with electromagnetism, which among the following is a correct definition of Permeability?
[A] Ability of a material to repel magnetic field within itself
[B] Ability of a material to support the formation of a magnetic field within another body
[C] Ability of a material to support the formation of a magnetic field within itself
[D] Ability of a material to create magnetic dipoles
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Correct Answer: C [Ability of a material to support the formation of a magnetic field within itself]
Notes:
Ability of a material to support the formation of a magnetic field within itself is Permeability. It is the measure of the resistance of a material against the formation of a magnetic field.
3. Whenever there are high winds, such as in storms, thin metal roofs on sheds as well as concave roofs on huts are sometimes blown away. Which among the following explains this correctly?
[A] During windstorm , the atmospheric pressure above the roof is very high in comparison to below the roof
[B] During windstorm , the atmospheric pressure above the roof is very low in comparison to below the roof
[C] The high velocity wind exerts tangential force on the roof surface
[D] The high velocity wind exerts vertical force on the roof surface
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Correct Answer: B [During windstorm , the atmospheric pressure above the roof is very low in comparison to below the roof]
Notes:
During the storm, the velocity of wind above the roof surface is very high and hence pressure is low. The pressure below the roof is atmospheric which is higher than the pressure of upper surface. Due to this pressure difference, the roof blows.
4. When you throw a ball with an angle to the horizontal (projectile); the ball has __:
[A] Uniform velocity in horizontal direction but uniform acceleration in vertical direction
[B] Uniform acceleration in horizontal direction but uniform velocity in vertical direction
[C] Uniform acceleration in both horizontal and vertical directions
[D] Uniform velocity in both horizontal and vertical directions
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Correct Answer: A [ Uniform velocity in horizontal direction but uniform acceleration in vertical direction]
Notes:
The motion of a projectile is two dimensional motion consisting of (i) horizontal motion and (ii) vertical motion. Hence, at any instant, the velocity of a projectile has two components (i) horizontal component and (ii) vertical component. The horizontal component remains unchanged throughout the flight as there is no acceleration in horizontal direction. The vertical component is continuously affected by the force of gravity. Thus, the horizontal motion is uniform motion but the vertical motion is uniformly accelerated motion.)
5. An Electric generator is based on which of the following scientific principles?
[A] Faraday’s law of Electromagnetic Induction
[B] Super Conductivity
[C] Laws of Thermodynamics
[D] Newton’s Law of Motion
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Correct Answer: A [Faraday’s law of Electromagnetic Induction]
Notes:
An Electric generator works on the principle of Faraday’s law of Electromagnetic Induction. An electric generator uses mechanical energy to generate electricity applying Faraday’s law of induction. It spins a coil at a constant rate in a magnetic field to induce an oscillating emf.
6. Among the following units, which one represents the smallest measurement of length?
[A] Micron
[B] Nanometer
[C] Fermi
[D] Angstrom
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Correct Answer: C [Fermi]
Notes:
In the presented choices, the Fermi stands as the smallest unit of length measurement. It is equal to 10^-15 m. Comparatively, 1 Micron equals 10^-6 m, 1 Nanometer equals 10^-9 m, and 1 Angstrom equivalent to 10^-10 m. All these units are commonly used to measure minuscule distances, particularly in the realm of nanotechnology and particle physics. However, the Fermi, named after the esteemed physicist Enrico Fermi, remains the smallest.
7. The equation of motion ‘v = u +at’ can be applied in which of the following cases?
[A] simple harmonic motion
[B] circular motion
[C] when acceleration is constant
[D] Both b and c
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Correct Answer: C [when acceleration is constant]
Notes:
The equation of motion ‘v = u +at’ can be applied only when the acceleration is constant. It cannot be applied in the cases of simple harmonic motion and circular motion.
8. Which of the these physical quantities is a vector quantity?
[A] Temperature
[B] Speed
[C] Gravitational Intensity
[D] Work
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Correct Answer: C [Gravitational Intensity]
Notes:
The physical quantities which have both magnitude and direction are called as Vector quantities. Some examples of Vector quantities: Acceleration, Velocity, Torque, Displacement, Gravitational Intensity, Force.
9. The second law of motion gives us a measure of which of the following physical quantities?
[A] Acceleration
[B] Force
[C] Power
[D] Work done
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Correct Answer: B [Force]
Notes:
The second law of motion gives us a measure of force. The product of the mass of the body and the acceleration produced in it gives us the magnitude of force. Force (f) = mass (m) x acceleration (a) Force is a vector quantity and the direction is same as that of acceleration
10. The distance of Neptune and Saturn from sun are nearly 1013 and 1012 meters respectively. Assuming that they move in circular orbits, what will be the ratio of their periodic times?
[A] 40
[B] 10√10
[C] 20√20
[D] 30√30
Show Answer
Correct Answer: B [10√10]
Notes:
By using Kepler’s third law, Tneptune/Tsaturn = (Rneptune/Rsaturn)3/2
