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. What is the mean value of g at earth’s surface?
[A] 0.98 meter per second
[B] 9.8 meter per second
[C] 9.8 meter per second square
[D] 0.98 meter per second square
Show Answer
Correct Answer: C [9.8 meter per second square]
Notes:
The mean value of the acceleration due to gravity (often denoted as “g”) at Earth’s surface is approximately 9.81 meters per second squared (m/s²). This value represents the average gravitational acceleration experienced by objects on the surface of the Earth. It is important to note that this value is not constant everywhere on Earth’s surface and can vary slightly due to factors such as location, altitude, and the density of the Earth’s crust.
2. Which of the following term denotes the internal reaction force per unit area developed as a result of applied external force ?
[A] Stress
[B] Friction
[C] Moment of Inertia
[D] tension
Show Answer
Correct Answer: A [Stress]
Notes:
Stress is the force acting per unit area. It is the internal force reaction per unit area developed as a result of external force.
3. Ohm is a unit of measuring _________?
[A] Resistance
[B] Voltage
[C] Current
[D] None of the above
Show Answer
Correct Answer: A [Resistance]
Notes:
The ohm is the SI unit of electrical resistance. Electrical resistance of an object is the measure of its obstruction to the flow of electric current. It mainly depends on the material it is made of, cross sectional area of a conductor, length and temperature. The resistance of a conductor of unit cross-sectional area and unit length is known as Resistivity. The unit of resistivity is ohm-metre.
4. Which of the following lie in the Tetra hertz frequency?
[A] Visible Light and Infra Red
[B] Infra Red and Microwaves
[C] Microwaves and Radio Waves
[D] Visible Light and Ultraviolet light
Show Answer
Correct Answer: B [ Infra Red and Microwaves]
Notes:
The range of the tera hertz radiation frequency is from roughly 0.1 THz to 10 THz. It is higher than the frequency of radio waves and microwaves, but lower than the frequency of infrared light.
5. A pressure cooker on a stove with its lid tightly closed and the whistle in position is an example of:
[A] open system
[B] closed system
[C] isolated system
[D] adiabatic system
Show Answer
Correct Answer: B [ closed system]
Notes:
A pressure cooker on a stove with its lid tightly closed and the whistle in position is an example of a closed-system thermodynamic process. In a closed-system thermodynamic process, the container (in this case, the pressure cooker) is sealed, and there is no exchange of matter with the surroundings. The pressure cooker is designed to be airtight, so no air or steam can escape while it’s cooking. This sealed environment allows for the buildup of pressure and temperature inside the cooker, which, in turn, speeds up the cooking process.
6. Which of the these physical quantities is a vector quantity?
[A] Temperature
[B] Speed
[C] Gravitational Intensity
[D] Work
Show Answer
Correct Answer: C [Gravitational Intensity]
Notes:
The physical quantities which have both magnitude and direction are called as Vector quantities. Some examples of Vector quantities: Acceleration, Velocity, Torque, Displacement, Gravitational Intensity, Force.
7. 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.
8. As per the Newton’s second law of motion, what is the relation between the rate of change of linear momentum and the external force applied?
[A] directly proportional
[B] inversely proportional
[C] independent of each other
[D] None of the above
Show Answer
Correct Answer: B [inversely proportional]
Notes:
As per the Newton’s second law of motion, the rate of change of linear momentum of a body is inversely proportional to the external force applied on the body. This change always takes place in the direction of the force applied.
9. An earth satellite S has an orbit radius which is 2 times that of a communication satellite C. What will be the period of revolution of S?
[A] 1 day
[B] 2 days
[C] 4 days
[D] 8 days
Show Answer
Correct Answer: C [4 days]
Notes:
As per Kepler’s third law, the square of the period of any planet is proportional to the cube of the semimajor axis of its orbit. Ts/Tc = 23/2= 4 days
10. What is the effect of increase in radius of orbit on the binding energy of a satellite?
[A] it increases
[B] it decreases
[C] It remains the same
[D] None of the above
Show Answer
Correct Answer: B [it decreases]
Notes:
The binding energy of a satellite decreases with the increase in the radius of orbit. The binding energy of a satellite is inversely proportional to the radius of orbit.
