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. How the brain interprets the frequency of an emitted sound is called its __:
[A] Pitch
[B] Amplitude
[C] Intensity
[D] Timbre
Show Answer
Correct Answer: A [ Pitch]
Notes:
How the brain interprets the frequency of an emitted sound is called the pitch. Researchers have discovered a discrete region of the monkey brain that processes pitch, the relative high and low points of sound, by recognizing a single musical note played by different instruments.
3. When equal force acts for equal time on two masses, both gain:
[A] Same velocity
[B] Same acceleration
[C] Same kinetic energy
[D] Same momentum
Show Answer
Correct Answer: D [Same momentum]
Notes:
When equal force acts for equal time, impulse (F × t) is equal. Impulse equals change in momentum, so both bodies gain same momentum regardless of their masses. Velocity and acceleration depend on mass, so they will differ.
4. Which of the following is the largest practical unit of mass?
[A] Slug
[B] a.m.u
[C] Hyperkg
[D] C.S.L
Show Answer
Correct Answer: D [ C.S.L ]
Notes:
The largest practical unit of mass is called as Chandra Shekhar Limit (C.S.L) which is equivalent to 1.4 times the mass of Sun. Chandrasekhar limit is the maximum mass theoretically possible for a stable white dwarf star. This limiting value was named after Indian-born astrophysicist Subrahmanyan Chandrasekhar, who formulated it in 1930. Using Albert Einstein’s special theory of relativity and the principles of quantum physics, Chandrasekhar showed that it is impossible for a white dwarf star, which is supported solely by a degenerate gas of electrons, to be stable if its mass is greater than 1.44 times the mass of the Sun.
5. Which of the following units is NOT used for measuring length?
[A] Astronomical Unit
[B] Light year
[C] Par sec
[D] slug
Show Answer
Correct Answer: D [ slug ]
Notes:
Astronomical Unit, Light year and Par sec are the units used to measure very large distances whereas slug is a unit to measure heavy masses. 1 slug = 14.57 kg
6. The branch of mechanics which deals with the study of motion of material objects without taking into account the factors which cause motion is called as:
[A] Statics
[B] Kinematics
[C] Dynamics
[D] None of the above
Show Answer
Correct Answer: B [Kinematics]
Notes:
The branch of mechanics which deals with the study of motion of material objects without taking into account the factors which cause motion is called as Kinematics. The branch of mechanics which deals with the study of motion of material objects taking into account the factors which cause motion is called as Dynamics. The branch of mechanics which deals with the study of material objects at rest is called as Statics.
7. The equation of motion ‘v = u +at’ can be applied in which of the following cases?
[A] simple harmonic motion
[B] circular motion
[C] when acceleration is constant
[D] Both b and c
Show Answer
Correct Answer: C [when acceleration is constant]
Notes:
The equation of motion ‘v = u +at’ can be applied only when the acceleration is constant. It cannot be applied in the cases of simple harmonic motion and circular motion.
8. 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.
9. The value of coefficient of limiting friction does not depend on which of the following?
[A] nature of the surfaces in contact
[B] total area of the surfaces in contact
[C] material of the surfaces in contact
[D] All of the above
Show Answer
Correct Answer: B [total area of the surfaces in contact]
Notes:
The coefficient of static friction can be defined as the ratio of the limiting static friction and the normal reaction between the 2 surfaces. The value of coefficient of limiting friction depends: 1. Nature of the surfaces in contact. 2. Material of the surfaces in contact
10. Which of the following has an effect on the value of acceleration due to gravity?
[A] Shape of the earth
[B] Height above the earth surface
[C] Axial rotation of the earth
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
The value of acceleration due to gravity vary due to the following factors : (a) Shape of the earth (b) Height above the earth surface (c) Depth below the earth surface (d) Axial rotation of the earth
