General Science - Physics MCQs
Physics Objective (Multiple Choice) General Knowledge & General Science Questions & Answers for SSC-CGL, UPPSC, UPSC, NDA, CDS and UPSC Civil Services Prelims Examinations.
11. Consider the following physical quantities:
- Entropy
- Work
- Momentum
- Force
Which of the above are vector quantities?
[A] 1 & 2
[B] 2 & 3
[C] 3 & 4
[D] 1 & 4
Show Answer
Correct Answer: C [ 3 & 4]
Notes:
A quantity which depends on direction is called a vector quantity. A quantity which does not depend on direction is called a scalar quantity. Entropy and work are scalar quantities.
12. The propagation of the Radio Waves in the atmosphere of earth is affected by ___:
1. Reflection
2. Refraction
3. Diffraction
4. Absorption
Choose the correct option from the codes given below:
[A] Only 1, 2 & 3
[B] Only 1, 3 & 4
[C] Only 1, 2 & 4
[D] 1, 2, 3 & 4
Show Answer
Correct Answer: D [ 1, 2, 3 & 4]
Notes:
When radio waves enter into the Earth atmosphere from space some of the waves are absorbed by the electrons present in the ionosphere. Some of the waves are reflected and some of them face diffraction and diffraction due to differently dense medium of Earth atmosphere.
13. In which of the following respects, the ultra-violet radiations are similar to white light?
- Both obey the laws of reflection and refraction
- Both travel with same speed in vacuum
- Both are equally active chemically
- Both are scattered equally
Select the correct option from the codes given below:
[A] Only 1
[B] Only 1 & 2
[C] Only 1, 2 & 3
[D] 1, 2, 3 & 4
Show Answer
Correct Answer: B [ Only 1 & 2]
Notes:
Both obey the laws of reflection.
Both obey the laws of refraction.
Both travel with the speed of 3 × 108 ms–1.
Ultraviolet waves get readily scattered as compared to visible light
Ultraviolet waves are chemically more active than visible light
14. Which of the following makes a CD or DVD show rainbow pattern?
[A] Diffraction of the Light
[B] Thin-Film Interference of the light
[C] Scattering of the light
[D] Polarisation of the light
Show Answer
Correct Answer: A [ Diffraction of the Light]
Notes:
A CD or DVD has closely spaced tracks which work as a diffraction grating to form the familiar rainbow pattern seen when looking at a disk.
15. 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
Show Answer
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.
16. 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.
17. The force between charged particles is called as:
[A] Nuclear Force
[B] Gravitational Force
[C] Centrifugal Force
[D] Electromagnetic Force
Show Answer
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.
18. What is the time taken by the earth to complete one rotation about its axis with regard to a fixed star?
[A] Sidereal day
[B] Solar day
[C] Shake
[D] Tropical year
Show Answer
Correct Answer: A [Sidereal day]
Notes:
Sidereal day is the time taken by the earth to complete one rotation about its axis w.r.t a fixed star Solar day is the time taken by the earth to complete one rotation about its axis w.r.t the sun. Shake is the smallest practical unit of time 1 shake = 10-8s Tropical year: The year in which there is a total solar eclipse.
19. Which of the following units is NOT used for measuring length?
[A] Astronomical Unit
[B] Light year
[C] Par sec
[D] slug
Show Answer
Correct Answer: D [ slug ]
Notes:
Astronomical Unit, Light year and Par sec are the units used to measure very large distances whereas slug is a unit to measure heavy masses. 1 slug = 14.57 kg
20. 1 nautical mile is equivalent to which of the following?
[A] 1.44 x 1000 m
[B] 1.852 x 100 m
[C] 1.852 x 1000 m
[D] 1.44 x 100 m
Show Answer
Correct Answer: C [ 1.852 x 1000 m ]
Notes:nautical mile is a unit of length. 1 nautical mile is equal to 1.852 x 1000 m Other important units of length are:
- 1 mile = 1.609 x 1000 m
- 1 light year = 9.46 x 1015 m
- 1 AU = 1.5 x 1011m
- 1 Par sec = 3.1 x 1016m
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