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. The X-ray crystallography mainly uses which among the following properties of electromagnetic radiation?
[A] Reflection
[B] Diffraction
[C] Interference
[D] Refraction
Show Answer
Correct Answer: B [ Diffraction]
Notes:
X-ray crystallography helps to determine the atomic and molecular structure of a crystal. The crystalline structure performs the diffraction and it causes a beam of incident X-rays to diffract into many specific directions.
2. Which among the following Radio frequencies are used around the world in air navigational system?
[A] Very Low Frequency (VLF)
[B] Very High Frequency (VHF)
[C] Tetrahertz Radiation (THF)
[D] Ultra High Frequency (UHF)
Show Answer
Correct Answer: B [ Very High Frequency (VHF)]
Notes:
VHF (Very High Frequency) omnidirectional radio range (VOR), is a short-range radio navigation system for aircraft, enabling aircraft to determine their position and stay on course by receiving radio signals transmitted by a network of fixed ground radio beacons, with a receiver unit. Uses radio frequencies in the very high frequency (VHF) band from 108 to 117.95 MHz. VOR is the standard air navigational system in the world, used by both commercial and general aviation.
3. Which of the following lie in the Tetra hertz frequency?
[A] Visible Light and Infra Red
[B] Infra Red and Microwaves
[C] Microwaves and Radio Waves
[D] Visible Light and Ultraviolet light
Show Answer
Correct Answer: B [ Infra Red and Microwaves]
Notes:
The range of the tera hertz radiation frequency is from roughly 0.1 THz to 10 THz. It is higher than the frequency of radio waves and microwaves, but lower than the frequency of infrared light.
4. On heating a pure silicon circular disc with a circular hole at the centre, the diameter of the hole:
[A] will expand
[B] will contract
[C] will remain constant
[D] may expand or contract
Show Answer
Correct Answer: B [ will contract]
Notes:
Pure silicon has a negative coefficient of thermal expansion for temperatures and hence it shows contraction effect.
5. If a Candle is make to burn in Zero Gravity__:
[A] The Candle will burn for a very long time compared to normal gravity
[B] The flame of the candle will become round
[C] There is no impact of gravity on the burning of candle
[D] The Candle will not burn in zero gravity
Show Answer
Correct Answer: B [ The flame of the candle will become round]
Notes:
Gravity plays a role in flame formation. Modifying the gravity causes different flame types. The common distribution of a flame under normal gravity conditions depends on convection, as soot tends to rise to the top of a general flame, as in a candle in normal gravity conditions, making it yellow. In micro gravity or zero gravity, such as an environment in outer space, convection no longer occurs, and the flame becomes spherical, with a tendency to become more blue and more efficient (although it may go out if not moved steadily, as the CO2 from combustion does not disperse as readily in micro gravity, and tends to smother the flame).
6. What is the value of Triple point of water?
[A] 273.16 K
[B] 273.16° C
[C] 0° C
[D] -273.16 K
Show Answer
Correct Answer: A [ 273.16 K ]
Notes:
Triple point of water is the temperature at which ice, water and water vapours coexist. The value of Triple point of water is 273.16 K Kelvin is the S.I unit of Temperature represented by symbol K.
7. Which of the following pairs represent two scalar quantities?
[A] Mass, Acceleration
[B] Temperature, Torque
[C] Distance, Speed
[D] Gravitational Intensity, Work
Show Answer
Correct Answer: C [Distance, Speed]
Notes:
The physical quantities which have only magnitude and no direction are called as Scalar quantities. Some examples of Scalar quantities: Work, Mass, Temperature, Distance, Speed.
8. The magnitude of the resultant of two vectors is maximum in which of the following case?
[A] when vectors act in the same direction
[B] when vectors act in the opposite direction
[C] when vectors act at 90° to each other
[D] None of the above
Show Answer
Correct Answer: A [when vectors act in the same direction]
Notes:
The magnitude of the resultant of two vectors is maximum when vectors act in the same direction. The magnitude of the resultant of two vectors is minimum when vectors act in the opposite directions.
9. Two vectors are said to be equal if:
[A] they have equal magnitude and same direction
[B] they have equal magnitude and opposite direction
[C] they have equal magnitude and common initial point
[D] they have equal magnitude irrespective of the direction
Show Answer
Correct Answer: A [they have equal magnitude and same direction]
Notes:
Two vectors are said to be equal if they have equal magnitude and same direction. Two vectors are said to be co-initial if their initial point is common.
10. Which of the following conditions is true for two vectors to be collinear?
[A] Equal magnitude
[B] Same Direction
[C] Acting along the parallel straight lines
[D] Both a and c
Show Answer
Correct Answer: C [Acting along the parallel straight lines]
Notes:
Two vectors are said to be collinear if they are acting along the parallel straight lines. The collinear vectors may or may not have equal magnitude.
