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MCQ of Gravitation:

Gravitation and Gravity

 
(1) The S.I unit of weight is
(a) \(m.{\sec ^{ - 1}}\)
(b) \(m.{\sec ^{ - 2}}\)
(c)  \(N.m\)
(d) \(N\)

(2) Inverse square law means
(a) \( \propto r\)
(b) \( \propto {r^{ - 1}}\)
(c) \( \propto {r^{ - 2}}\)
(d) \( \propto \frac{1}{{{r^{\frac{3}{2}}}}}\)

(3) The type of force that exists between two charges bodies is
(a) only gravitational
(b) only electrostatics
(c) neither (b) nor (b)
(d) both (b) and (b)

(4) As we go from equator to the poles, the value of 'g'
(a) remains the same
(b) decrease
(c) increases
(d)  decrease up altitude \(45^\circ \)
 
(5) Gravitational force is a 
(a) repulsive force
(b) action at a distance force
(c) neither (a) nor (b)
(d) both (a) and (b)

(6) A body weighs 72 N on the surface of the earth. Whar is the gravitational force on it due to earth earth at a height equal to half the radius of the earth from surface?
(a) 72 N
(b) 28 N
(c) 16 N
(d) 32 N

(7) If R is the radius of the earth, the height at which the weight of a body becomes \(\frac{1}{4}\) its weight on the surface of the earth is 
(a) 2R
(b) R
(c) \(\frac{R}{2}\)
(d)  \(\frac{R}{4}\)

(8) The value of 'g' is 
(a) Maximum at poles
(b) maximum at equator
(c) same everywhere
(d) minimum at pole

(9) An astronaut in the orbit in a spacecraft feels weightlessness
(a) due to the absence of gravity inside
(b) due to the fact that spacecraft has no energy
(c) because acceleration in the orbit is equal to acceleration of gravity outside
(d) There are no gravity outside.

(10) The value of 'g' at the center of the earth is 
(a) zero
(b) \(9.8m.{\sec ^{ - 2}}\)
(c) slightly greater than \(9.8m.{\sec ^{ - 2}}\)
(d) <\(9.8m.{\sec ^{ - 2}}\)

(11) Gravitational force is a 
(a) weakest force
(b) Strongest Force
(c) Short-range force
(d) non-central force



(12) The value of 'g' on the moon is  \(\frac{1}{6}th\) that on the earth. A body weighing 60 N on the earth, has weight on the moon as
(a) 20 N
(b) zero
(c) 360 N
(d) 10 N

(13) 1 kg-wt = 
(a) 5 N
(b) 9.8 N
(c) 19.6 N
(d) None of these

(14) If the diameter of the earth becomes two times its present value and its mass remains unchanged, then how would the weight the weight of an object on the surface of the earth be effected?
(a) Weight would become one-third
(b) Weight would become one-fourth
(c) Weight would become one-fifth
(d) Weight would would become one-sixth

(15)  Atmosphere is held to the earth due to
(a) frictional force
(b) gravitational force
(c) electric force
(d) magnetic force.

(16) Newton's law of gravitation is valid in 
(a) laboratory
(b) only on the earth
(c) only in our solar system
(d) everywhere

(17) The weight of a body will increase significantly . if it taken to 
(a) the center of the earth
(b) the highest place of the earth
(c) the pole
(d) the equator

(18) A simple pendulum has a time period \({T_1}\) when on the earth surface and \({T_2}\) when taken to a height 'R' above the earth's surface, where 'R' is the radius of the earth, The value of \(\frac{{{T_2}}}{{{T_1}}}\) is
(a) 1
(b) \(\sqrt 2 \)
(c) 0.5
(d) 2

(19) The S.I unit of mass is
(a) gram
(b) pound
(c) newton
(d) kilogram

(20) If \({m_e}\) is the mass of a body on the surface of the earth and \({m_m}\) is the mass of the same body on the moon then
(a) \({m_e} = 6{m_m}\)
(b) \({m_e} < {m_m}\)
(c) \({m_e} > {m_m}\)
(d) \({m_e} = {m_m}\)

(21) Where will it be protable to purchase one kilogram sugar?
(a) At Poles
(b) At Equator
(c) At \(45^\circ \) latitude
(d) At \(40^\circ \) latitude



(22) Two bodies of masses 2 kg and 8 kg are separated by a distance of 9 m. Then the point where the resultant gravitational field is zero is at a distance of
(a) 6 m from 8 kg
(b) 3 m from 8 kg
(c) 6 m from 2 kg
(d) 4,5 m from each mass

(23) A body falls through a distance 'h' in certain time on the earth. Then if same body is related on another planet having mass and radius twice as the of the earth, the distance through which it falls in the same time is
(a) \(\frac{h}{2}\)
(b) \(2h\)
(c) \(h\)
(d) \(4h\)

(24) The weight of a body is measure to be 120 N on the earth. If it is taken to the moon, its weight will be about
(a) 120 N
(b) 60 N
(c) 20 N
(d) 720 N

(25) Suppose we have taken a stone to the centra of the earth
(a) its wight becomes zero
(b) Its weight increases
(c)  Its weight is unaffected
(d) Its mass increases

(26) The weight of a body of mass 5 kg is
(a) 69 N
(b) 79 N
(c) 49 N
'(d) 39 N

(27) The mass of a body is measured to be 12 kg on the earth. If it is taken to moon, its mass will be
(a) 12 kg
(b) 72 kg
(c) 10 kg
(d) 2 kg

(28) The weight of an object 
(a) is the gravity of the matter it contains
(b) refer to its inertia
(c) is the force with which it is attacted towards the earth
(d) is the the same as its mass but expressed in different units

(29) The earth attracts the moon with a gravitational force of  \({10^{20}}N\). Then the moon attracts the earth with the gravitational force of
(a) \({10^{ - 20}}N\)
(b) \({10^2}N\)
(c) \({10^{20}}N\)
(d) \({10^{10}}N\)

(30) When an object is thrown upward, the force of gravity is
(a) opposite to the same direction of motion
(b) in the same direction as the direction of motion
(c) becomes zero at the highest point
(d) increases as it rises up

(31) Communication satellites moves in the orbit of radius 44,400 km around the earth of such a satellite assuming that the only force acting on it is that due to the earth is (\({m_e} = 6 \times {10^{24}}kg\))
(a) \(0.4m.{\sec ^{ - 2}}\)
(b)  \(0.6m.{\sec ^{ - 2}}\)
(c)  \(0.2m.{\sec ^{ - 2}}\)
(d) \(0.1m.{\sec ^{ - 2}}\)

(32) A stone is dropped from the top of a tower. Its velocity after it has fallen 20 m is
(a) -10 m/s
(b) 10 m/s
(c) -20 m/s
(d) 20 m/s



(33) The universal constant of gravitational G has the unit
(a) N
(b) \(m.{\sec ^{ - 2}}\)
(c) \(N{m^2}k{g^{ - 2}}\)
(d) J

(34) The earth attracts a body of mass 1 kg on its surface with a force of
(a) 1 N
(b) \(6.67 \times {10^{ - 11}}N\)
(c) 9.8 N
(d) \(\frac{1}{{9.8}}N\)

(35) In vacuum, all freely falling objects
(a) have the same speed
(b) have the same velocity
(c) have the same acceleration
(d) have the same force

(36) The value of  'g' is
(a) constant everywhere in space
(b) constant everywhere on the surface of the earth
(c) greater at the pole than at the equator
(d) greater at the equator than at the pole

(37) When you put an object on a spring balance, what do you measure?
(a) weight
(b) force
(c) mass
(d) acceleration

(38) A balloon of mass 'm' is rising with a acceleration an 'a'. A fraction of its mass is detached from the balloon. Its acceleratiom will 
(a) decrease
(b) increase
(c) remains the same.
(d) none of these

(39) Two persons weighing 50 kg and 60 kg are seated across a table. If they are one metre apart, the gravitational force between them is
(a) \(5 \times {10^{ - 7}}N\)
(b) \(2 \times {10^{ - 7}}N\)
(c) \(4 \times {10^{ - 7}}N\)
(d) \(3 \times {10^{ - 7}}N\)

(40) The force of gravitation between two bodies does not depend on
(a) their separation
(b) the product of their masses
(c) the sum of their masses
(d) the gravitational constant
(41) The acceleration due to gravity
(a) has the same value is space
(b) has the same value everywhere on the earth
(c) varies with the latitude on the earth
(d) is greater on the moon due to its smaller diameter.

(42) A ball is thrown up, the value of 'g' will be
(a) zero
(b) positive
(c) negative
(d) negligible

(43) The value of G was first determined experimentally by
(a) Newton
(b) Henry Cavendish
(c) Kepler
(d) Galilio

(44) The force which is needed to make an object travel in a circular path is called
(a) Electrostatic Force
(b) Gravitational force
(c) Centripetal Force
(d) Centrifugal Force

(45) The S.I unit of 'g' 
(a) \(m.{\sec ^{ - 1}}\)
(b) \(m.{\sec ^{ - 2}}\)
(c) N
(d) \({m^2}k{g^{ - 2}}\)

(46) Which of the following statements is true?
(a) 'g' is same at all places on the surface of the earth.
(b) 'g' has its maximum value at the equator.
(c) 'g' is less at the earth's surface than at a height above it or a depth below
(d) 'g' is greater at the pole than at the equator.

(47) At a place, value of 'g' is less by 1% than its value on the surface of the earth (Radius of earth, R=6400 Km). The place is
(a) 64 km below the surface of the earth
(b) 64 km above the surface of the earth
(c) 30 Km above the surface of the earth.
(d) 32 Km below the surface of the earth.

(48) A body is projected up with a velocity equal to \(\frac{3}{4}th\) of the escape velocity from the surface of the earth. The height it reaches is (Radius of the earth is R)
(a) \(\frac{{10R}}{9}\)
(b) \(\frac{{9R}}{7}\)
(c) \(\frac{{9R}}{{16}}\)
(d) \(\frac{{10R}}{3}\)

(49) A spring balance is graduated on sea level. If a body is weighed with this balance at consecutively increasing heights from earth's surface, the weight indicated by the balance 
(a) will go on decreasing continuously 
(b) will go on increasing continuously
(c) will remain same
(d) will first increase and than decrease

(50) The acceleration due to gravity on a planet depends on its
(a) mass only
(b) radius only
(c) mass and radius
(d) none of these

(51) Which among the following is according to Kepler's third law
(a) \(\frac{{{T^2}}}{{{r^3}}} = \) constant
(b) \(\frac{{{r^3}}}{{{T^2}}} = \) constant
(c) \({r^2} \times {T^3} = \) constant
(d) \({r^3} \times {T^2} = \) constant

(52) The value of G is
(a) \(6.67 \times {10^{ - 11}}N{m^2}k{g^{ - 2}}\)
(b) \(6.67 \times {10^{ - 11}}N{m^{ - 2}}k{g^{ - 2}}\)
(c) \(6.67 \times {10^{ - 9}}N{m^2}k{g^{ - 2}}\)
(d) \(6.67 \times {10^{ - 9}}N{m^{ - 2}}k{g^{ - 2}}\)

(53) The escape velocity from a planet of mass 'M' and radius 'R' and acceleration due to gravity 'g' is given by
(a) \(2\sqrt {\frac{{gM}}{R}} \)
(b) \(\sqrt {2gR} \)
(c) \(\sqrt {\frac{{2gM}}{R}} \)
(d) \(\sqrt {\frac{{gM}}{R}} \)

(54) The force of gravitation between two bodies of mass 1 Kg each kept at a distance of 1 m is 
(a) \(6.67N\)
(b) \(6.67 \times {10^{ - 9}}N\)
(c)  \(6.67 \times {10^{ - 7}}N\)
(d) \(6.67 \times {10^{ - 11}}N\)

(55) The gravitational pull exerted by the earth on a body is called
(a) true weight
(b) gravitational mass
(c) apparent weight
(d) inertial mass

(56) Two bodies A and B of masses 100 gm and 200 gm respectively are dropped near the earth's surface. Let the acceleration of A and B be \({a_1}\) and \({a_2}\) respectively. Then
(a) \({a_1} = {a_2}\)
(b) \({a_1} < {a_2}\)
(c) \({a_1} > {a_2}\)
(d) \({a_1} \ne {a_2}\)

(57) At what height from the surface of the earth will the value of acceleration due to gravity be reduced by 36% from the value at the surface?
(a) 1500 Km
(b) 1200 Km
(c) 1000 Km
(d) 1600 Km



(58) If the radius of the earth were to be increased by a factor of 3, by what factor d its density have to be changed to keep 'g' the same?
(a) 3
(b) \(\frac{1}{3}\)
(c) 6
(d) \(\frac{1}{6}\)

(59) An apple falls towards the earth because the earth attracts it. The apple also attracts the earth by the same force. Why do we  not see the earth rising towards the apple?
(a) Acceleration of the earth is very large when compared to that apple.
(b) Acceleration of the earth is equal to that of apple
(c) Acceleration of the earth is neither high nor too low.
(d) Acceleration of the earth is very small when compared to that of apple

(60) A coin and a feather are dropped together in a vaccum. Then
(a) the coin will reach the ground fast
(b) the father will reach the ground first
(c) both will reach the ground at the same time
(d) the feather will not fall down

(61) Two particles are kept at a separation of distance 'r'. The gravitational force between them is proportional to
(a) r
(b) \({r^2}\)
(c) \(\frac{1}{r}\)
(d) \(\frac{1}{{{r^2}}}\)

(62) A ball is thrown vertically upwards. The acceleration due to gravity 
(a) is in the direction opposite to the direction of its motion
(b) is in the same direction as the direction of its motion
(c) increases as it comes down
(d) becomes zero at the highest point

(63) A stone dropped from the roof of a building takes 4 sec to reach the ground. The height of the building is
(a) 19.6 m
(b) 39.2 m
(c) 156.8 m
(d) 78.4 m

(64) A ball is thrown upwards and attains a maximum height of 100 m. Its initial speed was
(a) 9.8 m/s
(b) 44.2 m/s
(c) 19.6 m/s
(d) 98 m/s

(65) The value of G depends on
(a) mass of the bodies
(b) distance between the body
(c) some other masses kept nearby
(d) none of these
(66) According to Kepler's law the relationship between  \(T\) (time period of revolution of a planet) and \(r\) (the semi major axis of the ellipse) is
(a) \({T^2} \propto r\)
(b) \({T^2} \propto {r^2}\)
(c) \({T^2} \propto {r^3}\)
(d) \(T \propto {r^{\frac{3}{2}}}\)

(67) The value of acceleration due to gravity at the Mount Everest is 
(a) g
(b) >g
(c) <g
(d) zero

(68) As a body moved from the centre of the earth to a height from the surface of the earth
(a) the weight of the body first increases from zero to a certain value and then starts decreasing
(b) the weight of the body goes on increasing
(c) the weight of the body goes on decreasing.
(d) the weight of the body first decreases and then increase

(69) The unit of \(\frac{G}{g}\) is
(a) \(kg.{m^{ - 1}}\)
(b) \(kg.{m^{ - 2}}\)
(c) \({m^2}k{g^{ - 1}}\)
(d) \(m.k{g^{ - 1}}\)

(70) The value of 'g' 
(a) decreases with height from the surface of the earth.
(b) increases with height from the surface of the earth
(c) remains unchanged with the increase in height from the surface of the earth
(d) none of these
(71) The weight of an object 
(a) increases when taken from pole to the equator
(b) increases when taken from equator to the pole
(c) increases when height taken from Delhi to the top of Mount Everest.
(d) increase when taken from the surface of the earth to moon

(72) The value of 'g' is zero
(a) at the top of the atmosphere 
(b) at 20 km below the surface of the earth
(c) at 20 Km above the surface of the earth
(d) at the centre of the earth

(73) Choose the correct statement
(a) Weight is a vector quantity
(b) The weight of a body in interplanetary space is maximum. 
(c) Weight increases when the bodies go up 
(d) \(N = 1kg \times 1m.{\sec ^{ - 1}}\)

(74) If  \({G_e}\) is the value of universal gravitational constant at the earth and \({G_m}\) is the value of universal gravitational constant on the moon then
(a) \({G_e} = 6{G_m}\)
(b) \({G_e} < {G_m}\)
(c) \({G_e} > {G_m}\)
(d) \({G_e} = {G_m}\)

(75) Two masses 'm' and 'M' are kept at a distance 'r'. The ratio of the force exerted on 'm' due to 'M' and that of 'M' due to 'm' is equal to
(a) \(\frac{m}{M}\)
(b) \(\frac{M}{m}\)
(c) \(\frac{{mr}}{M}\)
(d) 1:1

(76) The time period of a Geo-stationary Satellite is 
(a) 24 hours
(b) 6 hours
(c) 365 hours
(d) none of these

(77) An iron block was weighed at equator and its value was found to be 1 N. When the same iron block is weighed at pole, its value is found to 'x', Then
(a) 1=x
(b) 1>x
(c) x>1
(d) can't say
(78) If the distance between two bodies becomes 6 times theoritical distance, then the force between them becomes
(a) 36 times
(b) 6 times
(c) 12 times
(d) \(\frac{1}{{36}}\) times

(79) The mass and the diameter of a planet are two times those of earth. If a second pendulum is taken to it, the time period of the pendulum in seconds is
(a) \(\frac{1}{{\sqrt 2 }}\)
(b) \(\frac{1}{2}\)
(c) 2
(d) \(2\sqrt 2 \)

(80) The gravitational force between two masses kept in air at a certain distance is 'x' N. The same two masses are now kept in water and the distance between them are same. The gravitational force between these masses in water is 'y' N. Then
(a) x=y
(b) x<y
(c) x>y
(d) can't say
(81) If the value of G on the surface of earth is \(6.673 \times {10^{ - 11}}N.{m^2}.k{g^{ - 2}}\) , then the value of G on the planet Jupiter is 
(a) \(12 \times 6.673 \times {10^{ - 11}}N.{m^2}.k{g^{ - 2}}\)
(b) \(\frac{{6.673}}{{12}} \times {10^{ - 11}}N.{m^2}k{g^{ - 2}}\)
(c) \(6.673 \times {10^{ - 11}}N.{m^2}.k{g^{ - 2}}\)
(d) \(\frac{{6.673}}{6} \times {10^{ - 11}}N.{m^2}k{g^{ - 2}}\)

(82) The three laws of planetary motion is given by 
(a) Aristotle
(b) Kepler
(c) Copernicus
(d) Tyco Brahe

(83) Two particle are kept at a separation \(r\). The gravitational force between them is proportional to
(a) \(r\)
(b) \({r^2}\)
(c) \(\frac{1}{r}\)
(d) \(\frac{1}{{{r^2}}}\)

(84) The universal constant of gravitation G has the unit 
(a) N
(b) \(m.{\sec ^{ - 2}}\)
(c) \(\left( {N{m^2}} \right)/k{g^{ - 2}}\)
(d) \(J\)

(85) The equation \(F = \frac{{G{m_1}{m_2}}}{{{r^2}}}\) is valid for 
(a) rectangular bodies
(b) circular bodies
(c) elliptical bodies
(d) spherical bodies

(86) The force acting on a ball due to the earth has a magnitude \({F_b}\) and that acting on the earth due to the ball has a magnitude \({F_e}\). Then
(a) \({F_b} = {F_e}\)
(b) \({F_b} > {F_e}\)
(c) \({F_b} < {F_e}\)
(d) \({F_e} = 0\)

(87) The force of gravitation between two bodies of mass \(1kg\) each kept at a distance of \(1m\) is
(a) \(6.67N\)
(b) \(6.67 \times {10^{ - 9}}N\)
(c) \(6.67 \times {10^{ - 7}}N\)
(d) \(6.67 \times {10^{ - 11}}N\)

(88) The earth attracts a body of mass \(1kg\) on its surface with a force of
(a) \(1N\)
(b) \(6.67 \times {10^{ - 11}}N\)
(c) \(9.8N\)
(d) \(\frac{1}{{9.8}}N\)

(89) A coin and a feather are dropped together in a vacuum.
(a) The coin will reach the ground first.
(b) The feather will reach the ground first.
(c) Both the bodies will reach the ground together
(d) The feather will not fall down

(90) Two bodies A and B of masses 100 gm and 200 gm respectively are dropped near the earth's surface. Let the acceleration of A and B be \({a_1}\) and \({a_2}\) respectively.
(a) \({a_1} = {a_2}\)
(b) \({a_1} < {a_2}\)
(c) \({a_1} > {a_2}\)
(d) \({a_1} \ne {a_2}\)

(91) Newton's law of gravitation is valid
(a) on the earth only
(b) On the moon only
(c) in the laboratory only
(d) everywhere

(92) The acceleration due to gravity is \(9.8m.{\sec ^{ - 2}}\) 
(a) much above the earth's surface
(b) near the earth surface
(c) deep inside the earth
(d) at the center of the earth

(93) The acceleration due to gravity near the moon surface is
(a) approximately equal to near the earth surface
(b) approximately six times that near the earth's surface
(c) approximately one-sixth of that near the earth's surface
(d) slightly greater than that near the earth surface

(94) A particle is taken to a height R above the earth's surface, where R is the radius of the earth. The acceleration due to gravity there is
(a) \(2.45m.{\sec ^{ - 2}}\)
(b) \(4.9m.{\sec ^{ - 2}}\)
(c) \(9.8m.{\sec ^{ - 2}}\)
(d) \(19.6m.{\sec ^{ - 2}}\)

(95) Consider a heavenly body that has mass \(2{M_e}\) and radius \(2{R_e}\), where \({M_e}\) and \({R_e}\) are the mass and the radius of the earth respectively. The acceleration due to gravity at the surface of this heavenly body is
(a) \(2.45m.{\sec ^{ - 2}}\)
(b) \(4.9m.{\sec ^{ - 2}}\)
(c) \(9.8m.{\sec ^{ - 2}}\)
(d) \(19.6m.{\sec ^{ - 2}}\)

(96) When a body is thrown up, the force of gravity is 
(a) in the upward direction
(b) in the downward direction
(c) zero
(d) in the horizontal direction

(97) The mass of a body is measured to be 12 Kg on the earth. If it is taken to the moon, its mass will be
(a) 12 Kg
(b) 6 Kg
(c) 2 Kg
(d) 72 Kg

(98) The weight of a body is 120 N on the earth. If it is taken to the moon, its weight will be about
(a) 120 N
(b) 60 N
(c) 20 N
(d) 720 N

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