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 of the following is responsible for the fact that Tennis ball bounces higher at high altitudes than in plains?
[A] Low Gravity
[B] High Gravity
[C] Less dense air
[D] Low atmospheric temperature
Show Answer
Correct Answer: C [ Less dense air ]
Notes:
The rarified air at high altitudes gives less resistance to ball.
2. What is the use of Venturimeter?
[A] to measure subdivisions of scale
[B] to measure wavelength of radio wave
[C] To measure friction
[D] to measure rate of flow of fluids
Show Answer
Correct Answer: D [to measure rate of flow of fluids]
Notes:
A Venturimeter is the device used to measure rate of flow of fluids. This device is based on the principle of Bernoulli’s Equation.
3. 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.
4. Which among the following is the most acceptable range of LEO (Low Earth orbit)?
[A] 350 – 2,600 kms
[B] 200-2000 kms
[C] 160 – 2,000 kms
[D] 160-1600 kms
Show Answer
Correct Answer: C [160 – 2,000 kms]
Notes:
This range is commonly used and accepted in the context of satellite orbits within the Earth’s atmosphere. It extends from approximately 160 kilometers (the Kármán line, which is often used as the boundary of space) to around 2,000 kilometers above the Earth’s surface.
5. Echoes are heard when we shout in an empty hall. But when the hall is full of people no echoes are heard why?
[A] Echoes are subdued in the noise of people
[B] Soft clothes of people absorb sound instead of reflecting it
[C] Destructive interference of sound takes place
[D] Excessive reverberations take place
Show Answer
Correct Answer: D [ Excessive reverberations take place]
Notes:
When we shout in an empty hall, we hear your own sound after a short time. This is because the empty room reflects the sound, so there is an echo.
When a hall is full of people, the sound produced is reflected multiple times by the people. This causes the sound to overlap with the original sound, so the listener can’t distinguish between the two.
For an echo to be heard, the surfaces need to reflect the sound, or there needs to be more clarity. For example, big open spaces are good for hearing echoes.
6. Who was the first scientist to discover Electrons?
[A] Albert Einstein
[B] Isaac Newton
[C] J.C. Bose
[D] J.J Thompson
Show Answer
Correct Answer: D [J.J Thompson]
Notes:
J.J Thompson was the first scientist to discover and identify the electrons and to make the discovery of the first subatomic particle. He was also the first scientist to find evidence for isotopes of a stable (non-radioactive) element in 1913, as part of his exploration into the composition of canal rays (positive ions). His experiments to determine the nature of positively charged particles led to the development of the mass spectrograph. J.J Thompson belonged to United Kingdom. He won the Nobel Prize in Physics in 1906 for his work on the conduction of electricity in gases.
7. 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
8. 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
9. Which of the following is true about displacement of an object?
[A] It is always equal to the distance travelled by the object
[B] It can be less than the distance travelled by the object
[C] It can be greater than the distance travelled by the object
[D] It always less than the distance travelled by the object
Show Answer
Correct Answer: B [It can be less than the distance travelled by the object]
Notes:
The displacement is the shortest distance between the initial and final position of an object in the given time. The displacement of an object is a vector quantity. It can be less than or equal to the distance but can never be greater than the distance travelled by that object
10. The acceleration at a given instant of time is called as:
[A] Average acceleration
[B] Instantaneous acceleration
[C] Variable acceleration
[D] Zero acceleration
Show Answer
Correct Answer: B [Instantaneous acceleration]
Notes:
The acceleration of an object at a given instant of time is called Instantaneous acceleration. When an object moves with variable acceleration, then it possesses different acceleration at different point of time.
