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. 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.
2. Whenever there are high winds, such as in storms, thin metal roofs on sheds as well as concave roofs on huts are sometimes blown away. Which among the following explains this correctly?
[A] During windstorm , the atmospheric pressure above the roof is very high in comparison to below the roof
[B] During windstorm , the atmospheric pressure above the roof is very low in comparison to below the roof
[C] The high velocity wind exerts tangential force on the roof surface
[D] The high velocity wind exerts vertical force on the roof surface
Show Answer
Correct Answer: B [During windstorm , the atmospheric pressure above the roof is very low in comparison to below the roof]
Notes:
During the storm, the velocity of wind above the roof surface is very high and hence pressure is low. The pressure below the roof is atmospheric which is higher than the pressure of upper surface. Due to this pressure difference, the roof blows.
3. While passing over an obstacle a light ray slightly bends round the corner. The phenomenon is known as__:
[A] Scattering
[B] Polarisation
[C] Diffraction
[D] Refraction
Show Answer
Correct Answer: C [ Diffraction]
Notes:
The phenomenon of light rays bending around the corners of obstacles is called diffraction. Diffraction refers to various phenomena that occur when a wave encounters an obstacle or a slit.
4. 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.
5. 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.
6. What is the S.I. unit for Luminous Intensity?
[A] mole
[B] ampere
[C] candela
[D] weber
Show Answer
Correct Answer: C [ candela ]
Notes:
The S.I. unit for Luminous Intensity is candela. The symbol used for candela is cd. Mole is the S.I unit for Quantity of Matter ampere is the S.I unit for Electric Current. Weber is the S.I unit for Magnetic Flux Luminous Intensity is the amount of light that a point source radiates in a given direction
7. The branch of mechanics which deals with the study of motion of material objects without taking into account the factors which cause motion is called as:
[A] Statics
[B] Kinematics
[C] Dynamics
[D] None of the above
Show Answer
Correct Answer: B [Kinematics]
Notes:
The branch of mechanics which deals with the study of motion of material objects without taking into account the factors which cause motion is called as Kinematics. The branch of mechanics which deals with the study of motion of material objects taking into account the factors which cause motion is called as Dynamics. The branch of mechanics which deals with the study of material objects at rest is called as Statics.
8. The inablity of a body to change its state of rest or motion is known as:
[A] Force
[B] Momentum
[C] Displacement
[D] Inertia
Show Answer
Correct Answer: D [Inertia]
Notes:
Inertia is the property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force. There are three types of Inertia: 1. Inertia of rest 2. Inertia of motion 3. Inertia of direction
9. As per the Newton’s second law of motion, what is the relation between the rate of change of linear momentum and the external force applied?
[A] directly proportional
[B] inversely proportional
[C] independent of each other
[D] None of the above
Show Answer
Correct Answer: B [inversely proportional]
Notes:
As per the Newton’s second law of motion, the rate of change of linear momentum of a body is inversely proportional to the external force applied on the body. This change always takes place in the direction of the force applied.
10. What is the coefficient of restitution for a perfectly elastic collision?
[A] 0
[B] 1
[C] -1
[D] 100
Show Answer
Correct Answer: B [1]
Notes:
For a perfectly elastic collision, the coefficient of restitution is equal to 1 as the velocity of separation after collision is equal to the velocity of approach before collision. For a perfectly inelastic collision, the coefficient of restitution is equal to 0 as the velocity of separation after collision is equal to 0. The coefficient of restitution or coefficient of resilience is the ratio of relative velocity of separation after collision and the velocity of approach before collision.
