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. A long Rail (approximately 700 meters) made up of steel is struck to produce a sound. The person standing on the other end of the rail would hear in which among the following pattern?
[A] He listens the sound waves once propagated via steel
[B] He listens the sound waves once propagated via air
[C] He listens the sound waves twice, first propagated via steel and second propagated via air
[D] He listens the sound waves twice, first propagated via air and second propagated via steel
Show Answer
Correct Answer: C [He listens the sound waves twice, first propagated via steel and second propagated via air]
Notes:
The correct answer is that the person hears the sound waves twice: first via steel and then via air. Sound travels faster in solids than in gases. in steel, it travels at about 5,960 m/s, while in air, it travels at approximately 343 m/s. Given the long distance of 700 meters, the sound will reach the person through the steel rail first, followed by the sound traveling through the air. This phenomenon illustrates the differences in sound propagation speeds in different media.
2. With reference to the nuclear energy, what is the Special Nuclear Material (SNM)?
[A] A nuclear material that is NOT capable of sustaining a chain reaction of nuclear fission
[B] A fissile material that is capable of sustaining a chain reaction of nuclear fission
[C] A fissile material that is NOT capable of sustaining a chain reaction of nuclear fusion
[D] A fissile material that is capable of sustaining a chain reaction of nuclear fusion
Show Answer
Correct Answer: B [ A fissile material that is capable of sustaining a chain reaction of nuclear fission]
Notes:
A nuclear fissile material that is capable of sustaining a nuclear reaction is called Special Nuclear Material.
3. Which among the following provides potential energy to an object?
[A] Its momentum
[B] It’s position
[C] It’s acceleration
[D] It’s shape
Show Answer
Correct Answer: B [ It’s position]
Notes:
The potential energy is defined as the energy that is stored in an object due to its position. Various types of potential energy include the gravitational potential energy (depends on its mass and its distance from the center of other object’s mass), the elastic potential energy, the electric potential energy.
4. What is the force of attraction between any two bodies by virtue of their masses is called?
[A] Electromagnetic Force
[B] Gravitational Force
[C] Centripetal Force
[D] Nuclear Force
Show Answer
Correct Answer: B [Gravitational Force]
Notes:
Gravitational Force is the force of attraction between any two bodies by virtue of their masses. It is a universal force and every object in the universe experiences gravitational force due to every other object.
5. Which of these branches of Physics deal with heat and temperature and their relation to energy and work?
[A] Geophysics
[B] Mechanics
[C] Atomic Physics
[D] Thermodynamics
Show Answer
Correct Answer: D [Thermodynamics]
Notes:
Thermodynamics is that branch of physics which deals with heat and temperature and their relation to energy (such as mechanical, electrical, or chemical energy) and work. The behaviour of these quantities is governed by the four laws of thermodynamics
6. 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.
7. By how much times the orbital speed of a satellite needs to be increased to make it escape the gravitational field?
[A] √3 times
[B] 4 times
[C] 2 times
[D] √2 times
Show Answer
Correct Answer: D [√2 times]
Notes:
It means that if the speed of a satellite orbiting close to the earth is made √2 times (or increased by 41%) then it will escape from the gravitational field.
8. What kinds of waves are the ultrasonic waves in air produced by a vibrating quartz crystal?
[A] Transverse
[B] Longitudinal
[C] Transverse and longitudinal
[D] None of the above
Show Answer
Correct Answer: B [Longitudinal]
Notes:
The ultrasonic waves in air produced by a vibrating quartz crystal are longitudinal waves.
9. Which of the following is correct about the electromagnetic waves?
[A] They require a solid medium to travel
[B] They can travel through vacuum
[C] Electromagnetic waves can only travel through gases
[D] None of the above
Show Answer
Correct Answer: B [They can travel through vacuum]
Notes:
Electromagnetic waves do not necessarily require a medium – they can travel through vacuum. Light, radio waves, X-rays, are all electromagnetic waves.
10. What is the speed of electromagnetic waves in vacuum?
[A] 1000 m/s
[B] 3 x 108 m/s
[C] 300000 m/s
[D] Different for different waves
Show Answer
Correct Answer: B [3 x 108 m/s]
Notes:
In vacuum, all electromagnetic waves have the same speed whose value is 299, 792, 458 m/s or nearly equal to 3 x 108 m/s.
