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. India’s first Nobel Prize for Physics was claimed in 1930 by the renowned physicist Sir C.V. Raman for his work in which among the following fields?
[A] Particle Physics
[B] Optics
[C] Thermodynamics
[D] Quantum Mechanics
Show Answer
Correct Answer: B [Optics]
Notes:
In 1930, C.V. Raman became the first person from Asia to be awarded a Nobel Prize in any field of science. CV Raman made significant contributions to the field of optics. He is best known for his discovery of the Raman effect, which is the scattering of light by molecules. This phenomenon is now known as Raman scattering. The date of the discovery, February 28, is now celebrated as National Science Day in India.
2. The value of acceleration due to gravity is __________?
[A] Minimum at equator and maximum at poles
[B] maximum at equator and minimum at poles
[C] equal at poles and equator
[D] None of the above
Show Answer
Correct Answer: A [Minimum at equator and maximum at poles]
Notes:
The value of acceleration due to gravity is maximum at equator. This is because the distance from the center is minimum at the equator.
3. If a moving body turns its speed to 1.5 times, what will be the impact on its kinetic energy?
[A] will become 1.5 times
[B] will become 3 times
[C] will become 2.25 times
[D] will become 6 times
Show Answer
Correct Answer: C [will become 2.25 times]
Notes:
Kinetic Energy is a product of half the Mass times Velocity Squared. When the velocity is doubled, the Kinetic energy would go up four times. If velocity is tripled, kinetic energy would go up nine times. If velocity is increased by 1.5 times the Kinetic energy would go up by 1.5×1.5=2.25 times.
4. How the brain interprets the frequency of an emitted sound is called its __:
[A] Pitch
[B] Amplitude
[C] Intensity
[D] Timbre
Show Answer
Correct Answer: A [ Pitch]
Notes:
How the brain interprets the frequency of an emitted sound is called the pitch. Researchers have discovered a discrete region of the monkey brain that processes pitch, the relative high and low points of sound, by recognizing a single musical note played by different instruments.
5. A cardboard is placed on a glass of water, and a ten paise coin is placed on the cardboard. If the cardboard is flicked suddenly in the direction parallel to its surface, then the cardboard flies away, but the coin falls in the glass.
The behaviour of the coin can be explained by which among the following properties?
[A] Momentum
[B] Acceleration
[C] Inertia
[D] Friction
Show Answer
Correct Answer: C [ Inertia]
Notes:
Inertia is the property of matter that is why it continues in its existing state of either rest or motion. It can be changed by an external force. Here in the question the coin falls in the glass even after the cardboard is flicked because it maintains its rest position by the nature of inertia.
6. An object is executing uniform circular motion. Which of the following quantities remain(s) constant during the object’s motion?
[A] Velocity and acceleration
[B] Speed and velocity
[C] Speed and acceleration
[D] Speed only
Show Answer
Correct Answer: D [ Speed only]
Notes:
The velocity of an object undergoing uniform circular motion is always changing (because the direction is always changing). Further, since the acceleration is centripetal, it must always point toward the center of the circle; so, as the object moves around the circle, the acceleration vector is also constantly changing direction. Notice that for an object in uniform circular motion, both the velocity and the acceleration are changing because the directions of these vectors are always changing, even though their magnitudes stay the same. In this question, only speed remains unchanged.
7. 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).
8. Linear momentum can be described in which of the following units?
[A] kgm2/s2
[B] kg/ms2
[C] kg/ms
[D] kgm/s
Show Answer
Correct Answer: D [ kgm/s ]
Notes:
The SI unit of Linear Momentum is kg m/s Linear Momentum = Mass(kg) x Velocity (m/s) Linear Momentum is the quantity of motion of a moving body. Dimensional Formula of Linear Momentum is [M1 L1 T-1]
9. The motion of an object under free fall is an example of which of the following?
[A] uniform velocity
[B] uniform acceleration
[C] zero acceleration
[D] non-uniform acceleration
Show Answer
Correct Answer: B [uniform acceleration]
Notes:
The motion of an object under free fall is a case of uniform acceleration. If an object is released from a height near the surface of earth, it accelerates downwards under the influence of a gravity pull with acceleration due to gravity.
10. Which of the following statements regarding vectors is NOT correct?
[A] A unit vector is dimensionless
[B] A vector cannot be divided by a vector
[C] A vector changes, when it is displaced to itself
[D] Current is not a vector quantity
Show Answer
Correct Answer: C [A vector changes, when it is displaced to itself]
Notes:
A unit vector is unit less and dimensionless. A vector cannot be divided by a vector as a vector cannot be divided by a direction. A vector does not change, when it is displaced to itself. Time, Pressure, Surface Tension, Current are some of the quantities that have direction but are not vectors. A physical quantity is a vector only when it follows commutative law of addition of vectors.