Physics MCQs
Topic Notes: Physics
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
1
What term describes the total quantity of matter contained within a steel ball?
Answer:
Mass
Mass is defined as the fundamental measure of the amount of matter in an object. It is an intrinsic property that remains constant regardless of the object's location or the gravitational field acting upon it, unlike weight, which is the force exerted by gravity on that mass.
2
The Newton is the SI unit for which of the following physical quantities?
Answer:
Weight and Force
The Newton (N) is the SI derived unit of force. Since weight is defined as the force exerted on an object due to gravity (W = mg), it is also measured in Newtons. Velocity is measured in meters per second, mass in kilograms, and acceleration in meters per second squared. Therefore, both weight and force share the Newton as their standard unit of measurement.
3
What is the standard SI unit for wave speed?
Answer:
Meter/second
Speed is defined as the distance traveled per unit of time. In the International System of Units (SI), distance is measured in meters (m) and time is measured in seconds (s). Therefore, the unit for speed, including wave speed, is meters per second (m/s). Hertz is the unit for frequency, while the meter is the unit for wavelength.
4
What is the standard dimensional formula for force?
Answer:
MLT^-2
According to Newton's second law, force is the product of mass and acceleration. Mass has the dimension M, and acceleration is the rate of change of velocity, which is length divided by time squared (LT^-2). Multiplying these gives the dimensional formula MLT^-2, which is fundamental in mechanics.
5
Which of the following physical quantities possesses the same SI unit as the force constant of a spring?
Answer:
Surface tension
The force constant (k) of a spring is defined by Hooke's Law as F = -kx, so its units are Newtons per meter (N/m). Surface tension is defined as force per unit length, which also has the SI units of Newtons per meter (N/m). Therefore, both quantities share the same dimensional formula and SI unit.
6
Which of the following units is specifically defined for measuring astronomical distances?
Answer:
Parsec
A parsec (parallax of one arcsecond) is a unit of length used to measure the large distances to astronomical objects outside the Solar System. It is equivalent to approximately 3.26 light-years. It is derived from the use of parallax and trigonometry to measure the distance to stars based on the Earth's orbit around the Sun.
7
Which of the following physical quantities is not considered a fundamental quantity in the International System of Units (SI)?
Answer:
Weight
In physics, fundamental quantities are those that are independent of other physical quantities. Mass, length, and time are base SI quantities. Weight is a derived quantity because it is defined as the force of gravity acting on an object's mass (W = mg), making it dependent on mass and gravitational acceleration.
8
The ratio of arc length to radius defines which physical quantity?
Answer:
Plane angle
In geometry and physics, the plane angle (theta) is defined as the ratio of the arc length (s) to the radius (r) of a circle, expressed as theta = s/r. It is a dimensionless quantity measured in radians.
9
What term describes physical quantities that are derived from fundamental quantities?
Answer:
Derived Quantities
In physics, fundamental quantities are the basic building blocks (like length, mass, and time) that are independent of other quantities. Derived quantities are those physical quantities that are expressed in terms of these fundamental quantities through mathematical relationships, such as velocity (length/time) or force (mass × acceleration).
10
What physical quantity is measured by a 'light year'?
Answer:
Distance
Despite the word 'year' in its name, a light year is a unit of distance, not time. It represents the total distance that light travels in a vacuum in one Julian year, which is approximately 9.46 trillion kilometers. It is commonly used in astronomy to measure vast distances between celestial objects.