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 true regarding Sound Waves?
[A] They are longitudinal waves and material medium is not required for their propagation
[B] They are transverse waves and material medium is required for their propagation
[C] They are longitudinal waves and material medium is required for their propagation
[D] They are transverse waves and material medium is not required for their propagation
Show Answer
Correct Answer: C [They are longitudinal waves and material medium is required for their propagation]
Notes:
The sound waves are longitudinal waves and material medium is not required for their propagation. The sound waves can travel through solid, liquid and gas.
2. Which among the following works while we wipe with a towel.?
[A] evaporation
[B] osmosis
[C] capillary action
[D] surface tension
Show Answer
Correct Answer: C [capillary action]
Notes:
Capillary action is the ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity. The capillary action is among the following works while we wipe with a towel.
3. Which among the following temperature scale is based upon absolute zero?
[A] Celsius
[B] Fahrenheit
[C] Kelvin
[D] Rankine
Show Answer
Correct Answer: C [Kelvin]
Notes:
Kelvin is the base unit of temperature (SI unit), having the unit symbol K. The Kelvin temperature scale has an absolute zero (0°K) below which temperatures do not exist. It is the lowest possible temperature. At this temperature there is no motion and no heat. It is equivalent to 0°K, or -273.15° C, or at -460° F.
4. A small quantity of water is placed in a small cavity made in a block of Ice at 0 degree centigrade. Which of the following will happen?
[A] the temperature of water will become zero and it will freeze
[B] the temperature of water will become zero but it will not freeze
[C] the temperature of the water will become zero and it will come out of the cavity
[D] the temperature of the water will become zero and ice will melt to merge with water
Show Answer
Correct Answer: B [the temperature of water will become zero but it will not freeze]
Notes:
When a small quantity of water is placed in a small cavity made in a block of Ice at 0 degree centigrade the temperature of water will become zero but it will not freeze.
5. 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.
6. 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.
7. What is the relation between velocity and acceleration at the highest point of projectile path?
[A] both are at an angle of 45° to each other
[B] both are perpendicular to each other
[C] both are at an angle of 180° to each other
[D] None of the above
Show Answer
Correct Answer: B [both are perpendicular to each other]
Notes:
At the highest point of projectile path, the velocity and acceleration are perpendicular to each other. At the highest point of projectile path, the projectile possesses velocity only along the horizontal direction.
8. Which of the following is NOT correct about units of work:
[A] 1 joule = 107 ergs
[B] 1 kg-m = 1 joule
[C] 1 kg-m = 9.8 joule
[D] 1 joule = 1 Nm
Show Answer
Correct Answer: B [1 kg-m = 1 joule]
Notes:Joule is the absolute unit of work in S.I 1 joule = 1 Nm
- 1 joule= 107 ergs (erg is the unit of work in c.g.s)
- 1 erg = 1 dyne cm
- Also, Kilogram-metre (kg-m) is the gravitational unit of work on S.I 1 kg-m = 9.8 j
9. Which of the following laws state that the orbits of the planets are ellipses, with the Sun at one focus of the ellipse?
[A] Kepler’s First law
[B] Kepler’s Second law
[C] Kepler’s Third law
[D] None of the above
Show Answer
Correct Answer: A [Kepler’s First law]
Notes:
Kepler’s First law: It is also known as law of orbits. It states that every planet revolves around the sun in an elliptical orbit. The sun is situated at one foci of the ellipse.
10. What do we call the minimum velocity with which a body must be projected up, so as to enable it to just overcome the gravitational pull?
[A] Orbital velocity
[B] Gravitational velocity
[C] Escape velocity
[D] None of the above
Show Answer
Correct Answer: C [Escape velocity]
Notes:
The minimum velocity with which a body must be projected up, so as to enable it to just overcome the gravitational pull, is known as Escape velocity. Ve = (2gR)1/2
