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 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).
2. What is the S.I unit of Coefficient of Mutual inductance?
[A] weber
[B] candela
[C] henry
[D] lambert
Show Answer
Correct Answer: C [ henry ]
Notes:
The unit of Coefficient of Mutual inductance is henry lambert is the S.I unit of Luminance weber is the S.I unit of Magnetic Flux candela is the S.I unit of Luminous Intensity
3. Which of the following statements regarding vectors is NOT correct?
[A] A unit vector is dimensionless
[B] A vector cannot be divided by a vector
[C] A vector changes, when it is displaced to itself
[D] Current is not a vector quantity
Show Answer
Correct Answer: C [A vector changes, when it is displaced to itself]
Notes:
A unit vector is unit less and dimensionless. A vector cannot be divided by a vector as a vector cannot be divided by a direction. A vector does not change, when it is displaced to itself. Time, Pressure, Surface Tension, Current are some of the quantities that have direction but are not vectors. A physical quantity is a vector only when it follows commutative law of addition of vectors.
4. The forces acting at a point are called as:
[A] Collinear forces
[B] Coplanar forces
[C] Concurrent forces
[D] Unit forces
Show Answer
Correct Answer: C [Concurrent forces]
Notes:
The forces which are acting at a point are called as concurrent forces. Note: When concurrent forces in equilibrium act on a body, the state of the body shall remain unchanged i.e. if the body is at rest, it will continue to be at rest. Similarly, a body will continue to move uniformly along the same straight line, if concurrent forces in equilibrium are applied on the body.
5. What should be the angle between force and displacement for maximum work to be done?
[A] 0°
[B] 90°
[C] 180°
[D] 30°
Show Answer
Correct Answer: A [0°]
Notes:
For maximum work, the angle between force and displacement should be 0°. W = Fs Cos 0° = Fs For zero work, the angle between force and displacement should be 90°. W = Fs Cos 90° = 0
6. Which of the following is true about universal gravitational constant in the case of two bodies each of unit mass having their centres placed at unit distance apart?
[A] It is equal to the force of attraction between them
[B] It is equal to twice the force of attraction between them
[C] It is equal to half the force of attraction between them
[D] It is equal to ten times the force of attraction between them
Show Answer
Correct Answer: A [It is equal to the force of attraction between them]
Notes:
The universal gravitational constant is equal to the force of attraction between two bodies each of unit mass having their centres placed at unit distance apart. F = Gm1m2/r When m1 and m2 = 1 and r=1 then F=G.
7. Which of the following laws state that the orbits of the planets are ellipses, with the Sun at one focus of the ellipse?
[A] Kepler’s First law
[B] Kepler’s Second law
[C] Kepler’s Third law
[D] None of the above
Show Answer
Correct Answer: A [Kepler’s First law]
Notes:
Kepler’s First law: It is also known as law of orbits. It states that every planet revolves around the sun in an elliptical orbit. The sun is situated at one foci of the ellipse.
8. Kepler’s second law is also known as:
[A] Law of periods
[B] Law of areas
[C] Law of orbits
[D] Law of Planets
Show Answer
Correct Answer: B [Law of areas]
Notes:
Kepler’s second law states that an imaginary line joining a planet and the sun sweeps out an equal area of space in equal amounts of time i.e. the areal velocity of the planet around the sun is constant. It is also known as Law of areas.
9. In comparison to the gravitational force the earth exerts on the moon, the gravitational force the moon exerts on earth ________?
[A] will be greater
[B] will be lesser
[C] will be same
[D] None of the above
Show Answer
Correct Answer: C [will be same]
Notes:
Earth and moon both exerts same force on each other, even though the mass of the moon is about 1.2% of the mass of the earth.
10. What is the ratio of change in configuration to the original configuration called as?
[A] Strain
[B] Stress
[C] Elasticity
[D] Rebound
Show Answer
Correct Answer: A [Strain]
Notes:
The ratio of change in configuration to the original configuration is called strain. Strain are of three types : 1. Linear 2. Volumetric 3. Shearing
