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. Mach number is a measure of which of the following?
[A] Speed
[B] Heat Transfer
[C] Static Pressure
[D] Volume
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Correct Answer: A [Speed]
Notes:
Mach number refers to the ratio of the velocity of a fluid to the velocity of sound in that fluid, named after Ernst Mach (1838–1916), an Austrian physicist and philosopher. Speed of sound is Mach 1 speed.
2. Which among the following is measured by an Odometer?
[A] Pressure
[B] Height
[C] Distance
[D] Velocity
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Correct Answer: C [Distance]
Notes:
An odometer is an instrument used for measuring the distance. It measures distance traveled by a vehicle such as a bicycle or car. The device may be electronic, mechanical, or a combination of the two.
3. Which of the following waves is called compression-dilation waves or longitudinal waves?
[A] Primary waves
[B] Secondary waves
[C] Love waves
[D] Rayleigh waves
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Correct Answer: A [Primary waves]
Notes:
Primary wave is also called compression-dilation or longitudinal waves. Secondary wave is called transversal wave. Love wave and Rayleigh wave are surface waves. P waves can pass through solid, liquid and gases and are also the fastest among the three main types of waves.
4. Due to which of the following phenomena, the coloured glass appears white when crushed into fine powder?
[A] Total Internal Reflection
[B] Diffraction
[C] Scattering
[D] Refraction
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Correct Answer: C [ Scattering]
Notes:
When the glass is crushed into fine powder the light incident is totally scattered without the absorption so due to the composite light crushed glass appears white.
5. Who gave the Theory of Relativity?
[A] Isaac Newton
[B] Archimedes
[C] Albert Einstein
[D] Galileo Galilei
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Correct Answer: C [Albert Einstein]
Notes:
Albert Einstein was the founder of Theory of Relativity. According to Einstein’s theory, mass m is equivalent to energy E given by the relation E = mc^2 where c is speed of light in vacuum. Albert Einstein was awarded the 1921 Nobel Prize in Physics for his contribution to the field of Theoretical Physics.
6. The force between charged particles is called as:
[A] Nuclear Force
[B] Gravitational Force
[C] Centrifugal Force
[D] Electromagnetic Force
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Correct Answer: D [Electromagnetic Force]
Notes:
Electromagnetic force is the force between charged particles. It can be attractive for unlike charges and repulsive for like charges. It does not need any intervening medium to act and is enormously strong as compared to gravitational force.
7. What is the S.I unit of Pressure Energy?
[A] Nm
[B] Watt
[C] Joule
[D] No units
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Correct Answer: C [ Joule ]
Notes:
Joule is the unit of Pressure energy. Pressure energy is the energy stored in a fluid due to the force per unit area applied onto it Pressure energy = Pressure x volume Its dimensional formula is M L2 T-2
8. The work done by a variable force is given by:
[A] area under the force curve and the displacement axis
[B] square of the area under the force curve and the displacement axis
[C] natural log of the area under the force curve and the displacement axis
[D] twice the area under the force curve and the displacement axis
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Correct Answer: A [area under the force curve and the displacement axis]
Notes:
The work done by a variable force is given by the area under the force curve and the displacement axis. W = Area ABCDA
9. Kepler’s second law is also known as:
[A] Law of periods
[B] Law of areas
[C] Law of orbits
[D] Law of Planets
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Correct Answer: B [Law of areas]
Notes:
Kepler’s second law states that an imaginary line joining a planet and the sun sweeps out an equal area of space in equal amounts of time i.e. the areal velocity of the planet around the sun is constant. It is also known as Law of areas.
10. What is the main cause of capillarity?
[A] difference in weight of fluids
[B] pressure difference
[C] temperature difference
[D] velocity gradient
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Correct Answer: B [pressure difference]
Notes:
The main cause of capillarity is the difference in pressures on two sides of (concave and convex) curved surface of liquid.
