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. Which of the following conditions is true for an object to be in equilibrium?
[A] No linear motion of the object
[B] No rotational motion of the object
[C] Minimum potential energy of the object
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
The conditions for equilibrium for an object: 1. There is no linear motion of the object i.e. the resultant force on the object is zero 2. There should not be any rotational motion of the object i.e. the torque on the object should be zero 3. The potential energy of the object should be minimum for stable equilibrium.
12. The force acting on a body for a short time are called as:
[A] Average force
[B] Momentum
[C] Impulse
[D] Tension
Show Answer
Correct Answer: C [Impulse]
Notes:
The force acting on a body for a short time are called as Impulse. Example: hitting a ball with a bat. Impulse = average force x time It is a measure of total effect of the force. Its unit is Ns
13. The work done by a variable force is given by:
[A] area under the force curve and the displacement axis
[B] square of the area under the force curve and the displacement axis
[C] natural log of the area under the force curve and the displacement axis
[D] twice the area under the force curve and the displacement axis
Show Answer
Correct Answer: A [area under the force curve and the displacement axis]
Notes:
The work done by a variable force is given by the area under the force curve and the displacement axis. W = Area ABCDA
14. What is the value of acceleration due to gravity at the centre of the earth?
[A] 1 N/kg
[B] 0
[C] -9.8 N/kg
[D] 9.8 N/kg
Show Answer
Correct Answer: B [0]
Notes:
The value of acceleration due to gravity at the centre of the earth is 0. g1 = g2(1 – d/R) As d = R in case of centre of earth, g1 = 0
15. What is the value of escape velocity for earth?
[A] 9.8 km s-2
[B] 1.6 km s-2
[C] 11.2 km s-2
[D] 7.92 km s-2
Show Answer
Correct Answer: C [11.2 km s-2]
Notes:
The value of escape velocity is different for different planets. For earth, this value is 11.2 km s-2.
16. What do we call the strain produced in a body when the deforming force produces a change in its shape without changing its volume?
[A] Linear Strain
[B] Volumetric Strain
[C] Shearing strain
[D] Thermal Strain
Show Answer
Correct Answer: C [Shearing strain]
Notes:
When the deforming force produces a change in the shape of the body without changing its volume, the strain produced is called shearing strain.
17. Which of the following is the SI unit of Kinematic viscosity?
[A] m3/s
[B] Kg/s
[C] m s-1
[D] m2/s
Show Answer
Correct Answer: D [m2/s]
Notes:
The SI unit of kinematic viscosity is the square meter per second [m2/s]. It is denoted by ν(nu).
18. What is the S.I unit of the propagation constant?
[A] radian metre
[B] radian per metre
[C] radian per second
[D] radian per centimetre
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Correct Answer: B [radian per metre]
Notes:
The SI unit of propagation constant is radian per metre. It is also known as the angular wave number and represented by K.
19. What is the effect on apparent frequency when the distance between the source of the sound and listener is decreased?
[A] it increases
[B] it decreases
[C] it remains same
[D] None of the above
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Correct Answer: A [it increases]
Notes:
As per the Doppler effect, when the distance between the source and listener is decreasing the apparent frequency increases. It means the apparent frequency is more than the actual frequency of sound.
20. What do we call the process in which heat is transferred from one place to the other without any intervening medium?
[A] Radiation
[B] Conduction
[C] Convection
[D] None of the above
Show Answer
Correct Answer: A [Radiation]
Notes:
The process in which heat is transferred from one place to the other without any intervening medium is called radiation.
