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. Which among the following is a source of Atomic Energy ?
[A] Iron
[B] Uranium
[C] Silver
[D] Platinum
Show Answer
Correct Answer: B [Uranium]
Notes:
Uranium is the most common fuel used to produce nuclear energy. Uranium is a nonrenewable energy source that is found in rocks all over the world. However, the specific type of uranium used to produce nuclear energy, called U-235, is rare.
2. Zero point energy is the lowest possible energy that a quantum mechanical physical system may have. “Who among the following proposed this concept?
[A] Max Planck
[B] Albert Einstein and Otto Stern
[C] Hendrik B. G. Casimir
[D] Gribbin, John
Show Answer
Correct Answer: B [Albert Einstein and Otto Stern]
Notes:
Albert Einstein and Otto Stern proposed the concept of Zeropoint energy. It is the lowest possible energy that a quantum mechanical physical system may have.
3. Which among the following defines gravitational mass?
[A] Ratio of weight of a body and acceleration due to gravity
[B] Ratio of Acceleration due to gravity and weight of a body
[C] matter contained in a body
[D] None of the above
Show Answer
Correct Answer: A [Ratio of weight of a body and acceleration due to gravity]
Notes:
Gravitational mass is the Ratio of weight of a body and acceleration due to gravity. Gravitational mass is the mass of a body as measured by its gravitational attraction for other bodies.
4. 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.
5. 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.
6. If a Candle is make to burn in Zero Gravity__:
[A] The Candle will burn for a very long time compared to normal gravity
[B] The flame of the candle will become round
[C] There is no impact of gravity on the burning of candle
[D] The Candle will not burn in zero gravity
Show Answer
Correct Answer: B [ The flame of the candle will become round]
Notes:
Gravity plays a role in flame formation. Modifying the gravity causes different flame types. The common distribution of a flame under normal gravity conditions depends on convection, as soot tends to rise to the top of a general flame, as in a candle in normal gravity conditions, making it yellow. In micro gravity or zero gravity, such as an environment in outer space, convection no longer occurs, and the flame becomes spherical, with a tendency to become more blue and more efficient (although it may go out if not moved steadily, as the CO2 from combustion does not disperse as readily in micro gravity, and tends to smother the flame).
7. A person weighing 80 Kg. is standing on an accurate scale in an elevator. The elevator is slowing down while moving downwards. In this case the scale will read__?
[A] 80 Kg.
[B] Less than 80 Kg
[C] More than 80 Kg
[D] Either less or more than 80 Kg
Show Answer
Correct Answer: C [More than 80 Kg]
Notes:
When the elevator is slowing down while moving downwards, that means there is an acceleration upwards. The gravitational force must be lesser than the normal force. Thus, during slowing down while moving downwards, the normal force on the feet of a passenger is greater than her weight. In this case the scale will read more than 80 kg.
8. The forces acting at a point are called as:
[A] Collinear forces
[B] Coplanar forces
[C] Concurrent forces
[D] Unit forces
Show Answer
Correct Answer: C [Concurrent forces]
Notes:
The forces which are acting at a point are called as concurrent forces. Note: When concurrent forces in equilibrium act on a body, the state of the body shall remain unchanged i.e. if the body is at rest, it will continue to be at rest. Similarly, a body will continue to move uniformly along the same straight line, if concurrent forces in equilibrium are applied on the body.
9. Which of the following is correct about the coefficient of limiting friction between any two surfaces in contact?
[A] it is equal to twice the tangent of angle of friction
[B] it is equal to twice the sine of angle of friction
[C] it is equal to the tangent of angle of friction
[D] it is equal to the sine of angle of friction
Show Answer
Correct Answer: C [it is equal to the tangent of angle of friction]
Notes:
The coefficient of limiting friction between any two surfaces in contact is equal to the tangent of angle of friction between them. u = tan Q where u = coefficient of limiting friction and Q = angle of friction
10. What is the product of the mass of the body and its velocity called as?
[A] Force
[B] Linear Momentum
[C] Energy
[D] Power
Show Answer
Correct Answer: B [Linear Momentum]
Notes:
Linear Momentum is the product of the mass of the body and its velocity. Linear Momentum (p) = mass(m) x velocity(v) p= mv Linear momentum is a vector quantity having the direction same as the direction of velocity of the body