What is the time taken by the earth to complete one rotation about its axis with regard to a fixed star?
[A] Sidereal day
[B] Solar day
[C] Shake
[D] Tropical year
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Correct Answer: A [Sidereal day]
Notes:
Sidereal day is the time taken by the earth to complete one rotation about its axis w.r.t a fixed star Solar day is the time taken by the earth to complete one rotation about its axis w.r.t the sun. Shake is the smallest practical unit of time 1 shake = 10-8s Tropical year: The year in which there is a total solar eclipse.
12.What is the S.I. unit for Luminous Intensity?
[A] mole
[B] ampere
[C] candela
[D] weber
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Correct Answer: C [ candela ]
Notes:
The S.I. unit for Luminous Intensity is candela. The symbol used for candela is cd. Mole is the S.I unit for Quantity of Matter ampere is the S.I unit for Electric Current. Weber is the S.I unit for Magnetic Flux Luminous Intensity is the amount of light that a point source radiates in a given direction
13.kg m2is the unit of which of the following physical quantities?
[A] Linear Momentum
[B] Angular Momentum
[C] Angular Impulse
[D] Moment of Inertia
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Correct Answer: D [ Moment of Inertia ]
Notes:
kg m2is the unit of Moment of Inertia. The moment of inertia is a physical quantity which describes how easily a body can be rotated about a given axis. It is a rotational analogue of mass. Moment of Inertia = mass x (radius of gyration)2
14.Which of the following are Polar vectors?
[A] Displacement
[B] Force
[C] Both a and b
[D] None
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Correct Answer: C [Both a and b]
Notes:
The polar vectors are those vectors which have a starting point or a point of application. Examples of Polar vector: Force, Displacement etc. Those vectors which represent rotational effect are called as axial vectors. Example: Angular velocity, Torque, Angular Momentum etc.
15.Angle of friction is _______:
[A] equal to angle of repose
[B] equal to twice the angle of repose
[C] is greater than the angle of repose
[D] is less than the angle of repose
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Correct Answer: A [equal to angle of repose]
Notes:
Angle of friction is equal to angle of repose. Angle of repose is the angle that the plane of contact between two bodies makes with the horizontal when the upper body is just on the point of sliding.
16.What is the product of the mass of the body and its velocity called as?
[A] Force
[B] Linear Momentum
[C] Energy
[D] Power
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Correct Answer: B [Linear Momentum]
Notes:
Linear Momentum is the product of the mass of the body and its velocity. Linear Momentum (p) = mass(m) x velocity(v) p= mv Linear momentum is a vector quantity having the direction same as the direction of velocity of the body
17.The dot product of two vectors A and B is equal to the product of magnitude of A and B and __________?
[A] cosine of the largest angle between them
[B] sine of the largest angle between them
[C] cosine of the smallest angle between them
[D] sine of the smallest angle between them
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Correct Answer: C [cosine of the smallest angle between them]
18.1 electron volt of energy is equal to ____?
[A] 3.6 x 106 J
[B] 1.6 x 10-19 J
[C] 3.6 x 10-19 J
[D] 1.6 x 10-18 J
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Correct Answer: B [1.6 x 10-19 J]
19.The Universal Gravitational Constant for two bodies is dependent on which of the following?
[A] Nature of the bodies
[B] Size of the bodies
[C] Nature of medium between the bodies
[D] None of the above
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Correct Answer: D [None of the above]
20.What do we call the minimum velocity with which a body must be projected up, so as to enable it to just overcome the gravitational pull?
[A] Orbital velocity
[B] Gravitational velocity
[C] Escape velocity
[D] None of the above
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Correct Answer: C [Escape velocity]