MCQOPTIONS

Explore topic-wise MCQs in Physics.

This section includes 101 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.

51.	"If we go away from the surface of the earth a distance equal to the radius of earth the value of "g" becomes?"
A.	One third.
B.	One nine
C.	One fourth.
D.	One eight.
Answer» D. One eight.

52.	"At the center of earth dt R, value of "g"?"
A.	Will be zero.
B.	Will remain constant.
C.	Will be maximum.
D.	Will be unity.
Answer» B. Will remain constant.

53.	The weight of a body is the gravitational force exerted on it?
A.	By another body.
B.	By the planet.
C.	By the earth.
D.	By the moon.
Answer» D. By the moon.

54.	Above the surface of the earth if we go to distance equal to double the radius of the earth, the value of 'g' will become?
A.	one-ninth
B.	one-half
C.	one-third
D.	one-fourth
Answer» B. one-half

55.	A body released inside the spacecraft does not fall relative to it, and it appears to be?
A.	Mass less.
B.	Weightless
C.	Heaviest
D.	Lightest
Answer» C. Heaviest

56.	G is called
A.	gravitational force
B.	gravitational attraction
C.	accelaration due to gravity
D.	gravitational constant
Answer» E.

57.	The mean radius of the earth is R, its angular speed on its own axis is w and the acceleration due to gravity at earth's surface is g. The cube of the radius of the orbit of a geo-stationary satellite will be
A.	R2w2 / g
B.	r2g / w
C.	R2g / w2
D.	RG w2
Answer» D. RG w2

58.	Geo-stationary satellite
A.	has a time period less than that of the earth's satellite
B.	revolves about the polar axis
C.	is stationary in the space
D.	moves faster than a near earth satellite
Answer» C. is stationary in the space

59.	A satellite is revolving around the sun in a circular orbit with uniform velocity v. If the gravitational force suddenly disappears, the velocity of the satellite will be
A.	v
B.	zero
C.	infinity
D.	2v
Answer» B. zero

60.	The escape velocity from earth is 11.2 km per sec. If a body is to be projected in a direction making an angle 45° to the vertical, then the escape velocity is
A.	11.2 km/sec
B.	11.2 * 2 km/sec
C.	7.7 km/sec
D.	12.81 km/sec
Answer» B. 11.2 * 2 km/sec

61.	If the change in the value of g at the height h above the surface of the earth is the same as at a depth x below it, then (both x and h being much smaller than the radius of the earth)
A.	x = 2 h
B.	x = h
C.	x = h2
D.	x = h/2
Answer» B. x = h

62.	If the radius of the earth were to shrink by 1% its mass remaining the same, the acceleration due to gravity on the earth's surface would
A.	decrease by 2%
B.	increase by 2%
C.	will increase by 9.8%
D.	remain unchanged
Answer» C. will increase by 9.8%

63.	What would be the duration of the year if the distance between the earth and the sun gets doubled?
A.	129 days
B.	365 days
C.	1032 days
D.	730 days
Answer» D. 730 days

64.	The value of 'g' at a particular point is 9.8 m/sec2 suppose the earth suddenly shrink uniformly to half its present size without losing any mass. The value of 'g at the same point (assuming that the distance of the point from the centre of the earth does not shrink) will become
A.	19.6 m/sec2
B.	4.9 m/sec2
C.	9.8 m/sec2
D.	2.45 m/sec2
Answer» D. 2.45 m/sec2

65.	Who among the following first gave the experimental velocity of G?
A.	Copernicus
B.	none of these
C.	Cavendish
D.	Brook Taylor
Answer» D. Brook Taylor

66.	When body is raised to a height equal to radius of earth, the P.E. change is
A.	2 MgR
B.	MgR/2
C.	MgR
D.	none of these
Answer» C. MgR

67.	If the radius of the earth were to shrink by one percent, its mass remaining the same, the acceleration due to gravity on the earth's surface would
A.	decrease
B.	remains unchanged
C.	increase
D.	none of these
Answer» D. none of these

68.	If the acceleration due to gravity of a planet is half the acceleration due to gravity of earth's surface and radius of planet is half the radius of the earth, the mass of planet in terms of mass of earth is
A.	Me/2
B.	Me/6
C.	Me/4
D.	Me/8
Answer» E.

69.	Two identical solid copper spheres of radius R placed in contact with each other. The gravitational attracton between them is proportional to
A.	R-2
B.	R-4
C.	R2
D.	R4
Answer» E.

70.	If escape velocity from the earth's surface is 11.2 km/sec. then escape velocity from a planet of mass same as that of earth but radius one fourth as that of earth is
A.	22.4 km/sec
B.	5.65 km/sec
C.	11.2 km/sec
D.	44.8 km/sec
Answer» B. 5.65 km/sec

71.	The distance between centre of the earth and moon is 384000 km. If the mass of the earth is 6 × 1024 kg and G = 6.66 × 10-11 Nm2/kg2. The speed of the moon is nearly
A.	4 km/sec
B.	8 km/sec
C.	11.2 km/sec
D.	1 km/sec
Answer» E.

72.	The centripetal force acting on a satellite orbiting round the earth and the gravitational force of earth acting on the satellite both equal F. The net force on the satellite is
A.	Zero
B.	F√2
C.	F
D.	2 F
Answer» D. 2 F

73.	The dimensions of universal gravitational constant are
A.	M L-1 T-2
B.	M-1 L3 T-2
C.	M2 L2 T-2
D.	M L2 T-2
Answer» C. M2 L2 T-2

74.	The radii of the earth and the moon are in the ratio 10 : 1 while acceleration due to gravity on the earth's surface and moon's surface are in the ratio 6 : 1. The ratio of escape velocities from earth's surface to that of moon surface is
A.	7.74 : 1
B.	10:01
C.	1.66 : 1
D.	6:01
Answer» B. 10:01

75.	A thin uniform, circular ring is rolling down an inclined plane of inclination 30° without slipping. Its linear acceleration along the inclined plane will be
A.	g/2
B.	g/3
C.	g/4
D.	2g/3
Answer» D. 2g/3

76.	A planet has twice the radius but the mean density is \[\frac{1}{4}th\] as compared to earth. What is the ratio of escape velocity from earth to that from the planet [MH CET 2004]
A.	0.12569444444444
B.	0.043055555555556
C.	East-west
D.	0.084027777777778
Answer» D. 0.084027777777778

77.	Imagine a light planet revolving around a very massive star in a circular orbit of radius R with a period of revolution T. If the gravitational force of attraction between planet and star is proportional to \[{{R}^{-\frac{5}{2}}}\], then \[{{T}^{2}}\] is proportional to [IIT 1989; RPMT 1997]
A.	\[{{R}^{3}}\]
B.	\[{{R}^{7/2}}\]
C.	\[\frac{n{{r}^{2}}}{{{({{x}^{2}}+{{r}^{2}})}^{3/2}}}\]
D.	\[{{R}^{3/2}}\]
Answer» C. \[\frac{n{{r}^{2}}}{{{({{x}^{2}}+{{r}^{2}})}^{3/2}}}\]

78.	The value of escape velocity on a certain planet is 2 km/s. Then the value of orbital speed for a satellite orbiting close to its surface is [DCE 2005]
A.	12 km/s
B.	1 km/s
C.	Cylindrical surfaces of a bar magnet
D.	\[2\sqrt{2}\,\,km/s\]
Answer» D. \[2\sqrt{2}\,\,km/s\]

79.	The ratio of the radii of planets A and B is \[{{k}_{1}}\] and ratio of acceleration due to gravity on them is \[{{k}_{2}}\]. The ratio of escape velocities from them will be [BHU 2002]
A.	\[{{k}_{1}}{{k}_{2}}\]
B.	\[\sqrt{{{k}_{1}}{{k}_{2}}}\]
C.	\[60{}^\circ \]
D.	\[\sqrt{\frac{{{k}_{2}}}{{{k}_{1}}}}\]
Answer» C. \[60{}^\circ \]

80.	The change in potential energy, when a body of mass m is raised to a height nR from the earth's surface is (R = Radius of earth) [MP PMT 1996]
A.	\[mgR\frac{n}{n-1}\]
B.	nmgR
C.	\[4\times {{10}^{-3}}\,N\]
D.	\[mgR\frac{n}{n+1}\]
Answer» E.

81.	Escape velocity on the earth [BHU 2001]
A.	Is less than that on the moon
B.	Depends upon the mass of the body
C.	\[\frac{2}{3}\]
D.	Depends upon the height from which it is projected
Answer» E.

82.	The angular velocity of rotation of star (of mass M and radius R) at which the matter start to escape from its equator will be [MH CET 1999]
A.	\[\sqrt{\frac{2G{{M}^{2}}}{R}}\]
B.	\[\sqrt{\frac{2GM}{g}}\]
C.	There will be repulsion between A and B and also x and y
D.	\[\sqrt{\frac{2GR}{M}}\]
Answer» D. \[\sqrt{\frac{2GR}{M}}\]

83.	The escape velocity from the surface of earth is \[{{V}_{e}}\]. The escape velocity from the surface of a planet whose mass and radius are 3 times those of the earth will be [MP PMT/PET 1998; JIPMER 2001, 02; Pb. PMT 2004]
A.	\[{{V}_{e}}\]
B.	\[3{{V}_{e}}\]
C.	\[qa\,B/m\]
D.	\[27{{V}_{e}}\]
Answer» B. \[3{{V}_{e}}\]

84.	The escape velocity of a projectile from the earth is approximately [DPMT 1982, 84; RPMT 1997; BHU 1998]
A.	11.2 m/sec
B.	112 km/sec
C.	\[\frac{{{\mu }_{o}}I\,(x\hat{j}-y\hat{i})}{2\pi ({{x}^{2}}+{{y}^{2}})}\]
D.	11200 km/sec
Answer» D. 11200 km/sec

85.	A missile is launched with a velocity less than the escape velocity. The sum of its kinetic and potential energy is [MNR 1986; MP PET 1995]
A.	Positive
B.	Negative
C.	\[\frac{2{{\mu }_{o}}}{\pi a}\]
D.	May be positive or negative depending upon its initial velocity
Answer» C. \[\frac{2{{\mu }_{o}}}{\pi a}\]

86.	Gas escapes from the surface of a planet because it acquires an escape velocity. The escape velocity will depend on which of the following factors : Mass of the planet Mass of the particle escaping Temperature of the planet Radius of the planet Select the correct answer from the codes given below: [SCRA 1994]
A.	I and II
B.	II and IV
C.	Zero
D.	I, III and IV
Answer» D. I, III and IV

87.	A body is projected vertically upwards from the surface of a planet of radius R with a velocity equal to half the escape velocity for that planet. The maximum height attained by the body is [KCET (Engg./Med.) 2002]
A.	R/3
B.	R/2
C.	Square of the magnetic field produced due to each of the wires
D.	R/5
Answer» B. R/2

88.	A body of mass m is placed on the earth?s surface. It is taken from the earth?s surface to a height \[h=3R\]. The change in gravitational potential energy of the body is [CBSE PMT 2002]
A.	\[\frac{2}{3}mgR\]
B.	\[\frac{3}{4}mgR\]
C.	Zero at all points inside the loop
D.	\[\frac{mgR}{4}\]
Answer» C. Zero at all points inside the loop

89.	If the radius of the earth were to shrink by 1% its mass remaining the same, the acceleration due to gravity on the earth's surface would [IIT 1981; CPMT 1981; MP PMT 1996, 97; Roorkee 1992; MP PET 1999; Kerala PMT 2004]
A.	Decrease by 2%
B.	Remain unchanged
C.	\[6.28\times {{10}^{-5}}\,T\]
D.	Increase by 1%
Answer» D. Increase by 1%

90.	Assertion : Gravitational field is zero both at centre and infinity. Reason : The dimensions of gravitational field is \[[L{{T}^{-2}}]\].
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	Electric field
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. Electric field

91.	Assertion : Space rockets are usually launched in the equatorial line from west to east. Reason : The acceleration due to gravity is minimum at the equator.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	3 : 1
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» C. 3 : 1

92.	Assertion : The principle of superposition is not valid for gravitational force. Reason : Gravitational force is a conservative force.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	\[\frac{{{\mu }_{0}}}{4\pi }NLI\]
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» F.

93.	Assertion : Gravitational potential of earth at every place on it is negative. Reason : Every body on earth is bound by the attraction of earth.
A.	If both assertion and reason are true and the reason is the correct explanation of the assertion.
B.	If both assertion and reason are true but reason is not the correct explanation of the assertion.
C.	\[d\overrightarrow{B}=\frac{{{\mu }_{0}}}{4\pi }{{i}^{2}}\,\left( \frac{d\overrightarrow{l\,}\times \overrightarrow{r\,}}{{{r}^{2}}} \right)\]
D.	If the assertion and reason both are false.
E.	If assertion is false but reason is true.
Answer» B. If both assertion and reason are true but reason is not the correct explanation of the assertion.

94.	If it is assumed that the spinning motion of earth increases, then the weight of a body on equator [RPMT 2003]
A.	Decreases
B.	Remains constant
C.	\[1.35\times {{10}^{-2}}\,weber/{{m}^{2}}\]
D.	Becomes more at poles
Answer» B. Remains constant

95.	The acceleration of a body due to the attraction of the earth (radius R) at a distance 2 R from the surface of the earth is (g = acceleration due to gravity at the surface of the earth) [MP PET 2003]
A.	\[\frac{g}{9}\]
B.	\[\frac{g}{3}\]
C.	\[4\pi {{\mu }_{0}}ni\]
D.	g
Answer» B. \[\frac{g}{3}\]

96.	The acceleration due to gravity near the surface of a planet of radius R and density d is proportional to [MP PET 2002; AIEEE 2004]
A.	\[\frac{d}{{{R}^{2}}}\]
B.	\[d{{R}^{2}}\]
C.	p : 4
D.	\[\frac{d}{R}\]
Answer» D. \[\frac{d}{R}\]

97.	An object weights 72 N on earth. Its weight at a height of R/2 from earth is [AIIMS 2000]
A.	32 N
B.	56 N
C.	2 : 1
D.	Zero
Answer» B. 56 N

98.	If radius of the earth contracts 2% and its mass remains the same, then weight of the body at the earth surface [CPMT 1997; KCET (Engg./Med.) 2001]
A.	Will decrease
B.	Will increase
C.	\[2B\]
D.	None of these
Answer» C. \[2B\]

99.	Two planets have the same average density but their radii are \[{{R}_{1}}\] and \[{{R}_{2}}\]. If acceleration due to gravity on these planets be \[{{g}_{1}}\] and \[{{g}_{2}}\] respectively, then [AIIMS 1985]
A.	\[\frac{{{g}_{1}}}{{{g}_{2}}}=\frac{{{R}_{1}}}{{{R}_{2}}}\]
B.	\[\frac{{{g}_{1}}}{{{g}_{2}}}=\frac{{{R}_{2}}}{{{R}_{1}}}\]
C.	If assertion is true but reason is false.
D.	\[\frac{{{g}_{1}}}{{{g}_{2}}}=\frac{R_{1}^{3}}{R_{2}^{3}}\]
Answer» B. \[\frac{{{g}_{1}}}{{{g}_{2}}}=\frac{{{R}_{2}}}{{{R}_{1}}}\]

100.	The mass of the earth is 81 times that of the moon and the radius of the earth is 3.5 times that of the moon. The ratio of the acceleration due to gravity at the surface of the moon to that at the surface of the earth is [MP PMT 1994]
A.	0.15
B.	0.04
C.	\[\sqrt{2}\]km/s
D.	6
Answer» B. 0.04