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. Speed of sound is maximum in which among the following?
[A] Solids
[B] liquids
[C] Gases
[D] Vaccum
Show Answer
Correct Answer: A [Solids]
Notes:
The speed of sound decreases when we go from solid to gaseous state.
2. 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.
3. Steam at 100 degree centigrade causes more severe burns. Which of the following phenomena will you use to explain this?
[A] Specific heat
[B] Latent heat
[C] Fusion
[D] Fission
Show Answer
Correct Answer: B [Latent heat]
Notes:
Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. So steam at 100 degree centigrade causes more severe burns.
4. On which of the following Inertia of an object depends ?
[A] Bulk
[B] Size
[C] Shape
[D] Mass
Show Answer
Correct Answer: D [Mass]
Notes:
Inertia is the resistance experienced by an object to any change in its velocity. This includes changes to the object’s speed, or direction of motion. Inertia of rest, Inertia of motion are the examples.
5. Two Flat mirrors are placed at an angle of 60° from each other. How many images will be formed of a Candle placed in between them?
[A] 3
[B] 4
[C] 5
[D] 6
Show Answer
Correct Answer: C [5]
Notes:
If two flat mirrors are placed at an angle ø. Then number of images of an object placed between mirrors are = (360/ø) – 1 .
Here ø = 60
So, number of images of candle = (360/60) -1
SO there will be 5 images.
6. One joule of work is said to be done when__:
[A] a force of 1 dyne causes a displacement of 1 cm.
[B] a force of 1 dyne causes a displacement of 1 m.
[C] a force of 1 N causes a displacement of 1 cm.
[D] a force of 1 N causes a displacement of 1 m.
Show Answer
Correct Answer: D [ a force of 1 N causes a displacement of 1 m.]
Notes:
The joule is the unit of energy in the International System of Units. It is equal to the work done on an object when a force of one Newton acts on that object in the direction of the force’s motion through a distance of one meter. One joule of work is said to be done when a force of 1 N causes a displacement of 1 m.
7. 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.
8. The frequency range of Ultra High Frequency (UHF) is __?
[A] 3 to 10 Megahertz
[B] 3 to 30 Megahertz
[C] 300 to 3000 Megahertz
[D] 300 to 30000 Megahertz
Show Answer
Correct Answer: C [ 300 to 3000 Megahertz]
Notes:
Ultra High Frequency (UHF) designates the ITU radio frequency range of electromagnetic waves between 300 Megahertz to 3 GHz (3,000 Megahertz).
9. A person weighing 80 Kg. is standing on an accurate scale in an elevator. The elevator is slowing down while moving downwards. In this case the scale will read__?
[A] 80 Kg.
[B] Less than 80 Kg
[C] More than 80 Kg
[D] Either less or more than 80 Kg
Show Answer
Correct Answer: C [More than 80 Kg]
Notes:
When the elevator is slowing down while moving downwards, that means there is an acceleration upwards. The gravitational force must be lesser than the normal force. Thus, during slowing down while moving downwards, the normal force on the feet of a passenger is greater than her weight. In this case the scale will read more than 80 kg.
10. What is the effect on velocities of the two bodies of equal masses when they undergo elastic collision in one dimension?
[A] remains same
[B] gets interchanged
[C] becomes twice of the original velocity
[D] becomes half of the original velocity
Show Answer
Correct Answer: B [gets interchanged]
Notes:
The velocities get interchanged when two bodies of equal masses undergo elastic collision in one dimension.
