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 measured using a Vernier Caliper?
[A] Dimensions
[B] Time
[C] Sound
[D] Temperature
Show Answer
Correct Answer: A [Dimensions]
Notes:
The Vernier caliper has a main scale and a sliding vernier scale which can measure nearest to 0.02 mm. It can be used to measure internal and the external dimensions of an object by using the smaller jaws at the top and the main jaws respectively. By using stems depth can be measured.
2. The speed of Sound is maximum in which of the following ?
[A] Air at zero degree C
[B] Air at 100 degree C
[C] Water
[D] Same in all
Show Answer
Correct Answer: C [Water]
Notes:The speed of sound in a medium is determined by the properties of that medium, primarily its density and elasticity. The speed of sound is fastest in solids, followed by liquids, and then gases. Let’s analyze the given options:
[A] Air at zero degrees Celsius: The speed of sound in air increases with temperature. At lower temperatures, the molecules in the air have less kinetic energy, which results in a slower speed of sound. So, the speed of sound in air at 0°C is slower compared to higher temperatures.
[B] Air at 100 degrees Celsius: As mentioned earlier, the speed of sound in air increases with temperature. So, the speed of sound in air at 100°C would be faster than at 0°C but still slower than in a solid or liquid.
[C] Water: The speed of sound in water is significantly faster than in air. Water is denser and more elastic than air, which allows sound waves to travel through it more quickly.
[D] same in all: This statement is not correct. The speed of sound varies depending on the medium. It is not constant and is definitely not maximum everywhere.
So, among the given options, the maximum speed of sound would be in “Water” (Option C).
3. Which of the following is an instrument for measuring electric charge or electrical potential difference?
[A] Ammeter
[B] Voltmeter
[C] Electrometer
[D] ohmmeter
Show Answer
Correct Answer: B [Voltmeter]
Notes:
Voltmeter is an instrument for measuring electric charge or electrical potential difference. It was invented by Hans Christian Oersted.
4. In which among the following, the speed of sound would be maximum?
[A] Dry air at 0°C
[B] Dry air at 30°C
[C] Humid air at 0°C
[D] Humid air at 30°C
Show Answer
Correct Answer: D [ Humid air at 30°C]
Notes:
The speed of sound in a medium depends on temperature of the medium. The speed of sound decreases when we go from solid to gaseous state. In any medium as we increase the temperature the speed of sound increases.. The speed of sound will be highest in humid air at 30°C.
5. Electron microscope works on which of the following principles?
[A] Optical interference
[B] Wave Nature of electrons
[C] Motion of charged particle in electromagnetic fields
[D] Faraday’s law of Electromagnetic induction
Show Answer
Correct Answer: B [Wave Nature of electrons]
Notes:
Electron microscope works on the principle of Wave Nature of electrons. Electron microscopes use an electron beam instead of visible light and an electron detector instead of our eyes. An electron beam allows us to see at very small scales because electrons can also behave as light due to its wave nature.
6. What is the S.I. unit for Luminous Intensity?
[A] mole
[B] ampere
[C] candela
[D] weber
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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. What is the maximum height that can be attained by a projectile?
[A] equal to its maximum range
[B] one half of its maximum range
[C] one-fourth of its maximum range
[D] twice of its maximum range
Show Answer
Correct Answer: C [one-fourth of its maximum range]
Notes:
The maximum height that can be attained by a projectile is equal to one-fourth of its maximum range.
8. Which of the following is NOT correct about the velocity of rocket at any time?
[A] it is directly proportional to the exhaust speed of the gases
[B] it is directly proportional to the natural log of ratio of intial mass of rocket to its mass at that instant
[C] length of the rocket
[D] All of the above
Show Answer
Correct Answer: C [length of the rocket]
Notes:
The velocity of rocket at any time is directly proportional to the exhaust speed of the gases and to the natural log of ratio of intial mass of rocket to its mass at that instant. V = u log(m1/m2)
9. The value of acceleration due to gravity is minimum on which of these planets?
[A] Mars
[B] Jupiter
[C] Mercury
[D] Neptune
Show Answer
Correct Answer: C [Mercury]
Notes:
The value of acceleration due to gravity is minimum on planet Mercury and maximum on planet Jupiter.
10. Which of the following is correct about the value of acceleration due to gravity?
[A] it is greater at mountains than in plains
[B] it is lesser at mountains than in plains
[C] it is equal for mountains and plains
[D] None of the above
Show Answer
Correct Answer: B [it is lesser at mountains than in plains]
Notes:
The value of acceleration due to gravity decreases with increase in height. Therefore, it is lesser at mountains than in plains.
