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 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.
2. A vehicle moving on a circular path experiences ________?
[A] centripetal force
[B] centrifugal force
[C] gravitational force
[D] None of the above
Show Answer
Correct Answer: A [centripetal force]
Notes:
A vehicle moving on a circular path experiences centripetal force. Centripetal force that acts on a body moving in a circular path and is directed towards the centre around which the body is moving.
3. The pointer or arrow of the magnetized needle of a compass indicates which among the following?
[A] Geographic North Pole
[B] Magnetic North Pole
[C] Geo-magnetic North Pole
[D] Magnetic South Pole
Show Answer
Correct Answer: D [ Magnetic South Pole]
Notes:
The north pole of a magnet in a compass points north because it is attracted to the Earth’s magnetic south pole, which is located near Earth’s geographic north pole. The geographic north pole of earth corresponds to magnetic south pole and geographic south pole of earth corresponds to magnetic north pole. The direction in which a compass needle points is known as magnetic north. This is not exactly the direction of the North Magnetic Pole. Instead, the compass aligns itself to the local geomagnetic field, which varies in a complex manner over the Earth’s surface. The angular difference between magnetic north and true north (defined in reference to the Geographic North Pole), at any particular location on the Earth’s surface, is called the magnetic declination. Most map coordinate systems are based on true north, and magnetic declination is often shown on map legends so that the direction of true north can be determined from north as indicated by a compass.
4. Which of the following makes a CD or DVD show rainbow pattern?
[A] Diffraction of the Light
[B] Thin-Film Interference of the light
[C] Scattering of the light
[D] Polarisation of the light
Show Answer
Correct Answer: A [ Diffraction of the Light]
Notes:
A CD or DVD has closely spaced tracks which work as a diffraction grating to form the familiar rainbow pattern seen when looking at a disk.
5. If a moving body turns its speed to 1.5 times, 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.
6. Joule/kg is the S.I unit of which of these physical quantities?
[A] Entropy
[B] Permittivity of free space
[C] Latent heat
[D] Gas constant
Show Answer
Correct Answer: C [ Latent heat ]
Notes:
Joule/kg is the S.I unit of Latent heat Latent heat(L) = heat(Q)/mass(m) Latent heat is the heat required to convert a solid into a liquid or vapor, or a liquid into a vapor, without any change in temperature. Unit of Entropy: J/K Unit of Permittivity of free space: H/m Unit of Gas constant : J/K
7. On which of the following quantities, Work done does not depend?
[A] Force applied
[B] Displacement
[C] Time
[D] Depends on all of the above
Show Answer
Correct Answer: C [Time]
Notes:
Work done does not depend on the time for which the force was applied. Work done is only dependant on the force and displacement. Time is involved in the case of Power only
8. The Universal Gravitational Constant for two bodies is dependent on which of the following?
[A] Nature of the bodies
[B] Size of the bodies
[C] Nature of medium between the bodies
[D] None of the above
Show Answer
Correct Answer: D [None of the above]
Notes:
The value of Universal Gravitational Constant is same throughout the universe. It is independent of nature of the bodies, size of the bodies and nature of medium between the bodies.
9. On which of the following factors the breaking stress depends?
[A] Area of cross-section
[B] length of the material
[C] Nature of the material
[D] None of the above
Show Answer
Correct Answer: C [Nature of the material]
Notes:
Breaking force = P × A Here P is a constant of proportionality and known as breaking stress. Breaking stress is constant for a given material and does not depend upon the dimension (length or thickness) of wire.
10. On which of the following principles is Hydraulic lift based?
[A] Pascal law
[B] Bernoulli’s principle
[C] Stoke’s law
[D] Torricelli’s law
Show Answer
Correct Answer: A [Pascal law]
Notes:
Pascal law states that whenever external pressure is applied on any part of a fluid contained in a vessel, it is transmitted undiminished and equally in all directions. This is another form of the Pascal’s law. Devices such as hydraulic lift and hydraulic brakes, are based on the Pascal’s law.
