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.
11. What is represented by the slope of a straight line joining two points on a velocity-time graph?
[A] Average velocity
[B] Instantaneous acceleration
[C] Average acceleration
[D] None of the above
Show Answer
Correct Answer: C [Average acceleration]
Notes:
The slope of a straight line joining two points on a velocity-time graph gives the average acceleration between these two points. Depending on the sign of slope, the average acceleration can be positive or negative.
12. 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.
13. What kind of energy is stored in the spring of a watch?
[A] Kinetic
[B] Potential
[C] Heat
[D] Chemical
Show Answer
Correct Answer: B [Potential]
Notes:
Potential energy is stored in the spring of a watch. Potential energy is the energy by virtue of an object’s position relative to other objects. It is often associated with restoring forces such as a spring or the force of gravity.
14. What will be the effect on the value of acceleration due to gravity at the poles if the rate of rotation of earth increases?
[A] No effect
[B] it will increase
[C] it will decrease
[D] it will become zero
Show Answer
Correct Answer: A [No effect]
Notes:
If the rate of rotation of earth increases then the value of acceleration due to gravity decreases at all the places on the surface of earth except at poles.
15. Water does not fall out of a glass when it is inverted inside a satellite, which is orbiting very close to the earth’s surface. Which of the following is the best reason for this?
[A] The earth does not exert any force on the water
[B] The earth’s force of attraction on the water is exactly balanced by the force created by the satellites
[C] The water and the glass have the same acceleration due to gravity
[D] The gravitational attraction between the glass and the water balances the earth’s attraction on the
Show Answer
Correct Answer: C [The water and the glass have the same acceleration due to gravity]
Notes:
Water does not fall out of a glass when it is inverted inside a satellite, which is orbiting very close to the earth’s surface. The reason for this is that the water and the glass have the same acceleration due to gravity, equal to g, towards the centre of the earth. Hence there is no relative motion between them.
16. 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.
17. What is the upward force experienced by a body, when it is immersed in a fluid, known as?
[A] Tangential force
[B] Buoyant force
[C] Centrifugal force
[D] Hydraulic force
Show Answer
Correct Answer: B [Buoyant force]
Notes:
When a body is immersed in a fluid (liquid or gas) it exerts an upward force on that body. This upward force is called up thrust or buoyant force, The whole phenomenon is called as buoyancy.
18. Which is the effect of increase in the temperature on the surface tension of the liquid?
[A] it decreases
[B] it increases
[C] it remains the same
[D] None of the above
Show Answer
Correct Answer: A [it decreases]
Notes:
The surface tension of liquid decreases with rise of temperature. The surface tension of a liquid is zero at its boiling point and it vanishes at critical temperature.
19. What do we call the distance of particle from the mean position at that instant in S.H.M?
[A] Distance
[B] Displacement
[C] Phase
[D] Angular frequency
Show Answer
Correct Answer: B [Displacement]
Notes:
The displacement of a particle executing S.H.M. at an instant is defined as the distance of particle from the mean position at that instant.
20. Which of the following waves are also called as heat waves?
[A] UV rays
[B] X-rays
[C] Infrared
[D] Micro waves
Show Answer
Correct Answer: C [Infrared]
Notes:
Infrared waves vibrate not only the electrons, but entire atoms or molecules of a substance. This vibration increases the internal energy and consequently, the temperature of the substance. Therefore, infrared waves are often called as heat waves.
