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. What is the mean value of g at earth’s surface?
[A] 0.98 meter per second
[B] 9.8 meter per second
[C] 9.8 meter per second square
[D] 0.98 meter per second square
Show Answer
Correct Answer: C [9.8 meter per second square]
Notes:
The mean value of the acceleration due to gravity (often denoted as “g”) at Earth’s surface is approximately 9.81 meters per second squared (m/s²). This value represents the average gravitational acceleration experienced by objects on the surface of the Earth. It is important to note that this value is not constant everywhere on Earth’s surface and can vary slightly due to factors such as location, altitude, and the density of the Earth’s crust.
3. Which of the following term denotes the internal reaction force per unit area developed as a result of applied external force ?
[A] Stress
[B] Friction
[C] Moment of Inertia
[D] tension
Show Answer
Correct Answer: A [Stress]
Notes:
Stress is the force acting per unit area. It is the internal force reaction per unit area developed as a result of external force.
4. Who gave the Theory of Relativity?
[A] Isaac Newton
[B] Archimedes
[C] Albert Einstein
[D] Galileo Galilei
Show Answer
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.
5. The apparent weight of the body becomes zero in which of the following cases in the elevator?
[A] during free fall of a body under gravity
[B] when elevator is accelerating downwards
[C] when elevator is at rest
[D] when elevator is accelerating upwards
Show Answer
Correct Answer: A [during free fall of a body under gravity]
Notes:
The apparent weight of the body becomes zero in an elevator during free fall of a body under gravity. It can be said that the body becomes weightless as the force of reaction between the person and the plane with which he is in contact vanishes.
6. In comparison to the gravitational force the earth exerts on the moon, the gravitational force the moon exerts on earth ________?
[A] will be greater
[B] will be lesser
[C] will be same
[D] None of the above
Show Answer
Correct Answer: C [will be same]
Notes:
Earth and moon both exerts same force on each other, even though the mass of the moon is about 1.2% of the mass of the earth.
7. Which of the following relations between Kinetic energy and Potential energy is true about solids?
[A] Kinetic energy = Potential energy
[B] Kinetic energy > Potential energy
[C] Kinetic energy >> Potential energy
[D] Kinetic energy < Potential energy
Show Answer
Correct Answer: D [Kinetic energy < Potential energy]
Notes:
In Solids, Kinetic energy is always less than the Potential energy. For liquids, Kinetic energy > Potential energy. For Gases, Kinetic energy >> Potential energy.
8. What is the maximum stress after which the wire breaks called as?
[A] Tensile strength
[B] Shear strength
[C] Bulk strength
[D] Hooke’s strength
Show Answer
Correct Answer: A [Tensile strength]
Notes:
The maximum stress after which the wire begin to flow and breaks, is called breaking stress or tensile strength. The force by application of which the wire breaks is called the breaking force.
9. What is the order of distance for interatomic forces to be active?
[A] 10–7 metre
[B] 10–8 metre
[C] 10–9 metre
[D] 10–10 metre
Show Answer
Correct Answer: D [10–10 metre]
Notes:
The forces between the atoms because of the electrostatic interaction between the charges of the atoms are called interatomic forces. These forces are active if the distance between the two atoms is of the order of atomic size i.e. 10–10 metre. These forces are electrical in nature.
10. What happens to a body when its density is greater than the density of the fluid?
[A] it floats
[B] it sinks
[C] it stays at rest
[D] None of the above
Show Answer
Correct Answer: B [it sinks]
Notes:
The body sinks in the fluid in case its density is greater than the density of the fluid. For example, an iron nail has greater density than water, therefore it sinks in water.
