CBSE Questions for Class 11 Engineering Physics Gravitation Quiz 7 - MCQExams.com

Weight of a body of mass m decreases by $$1 \%$$ when it is raised to height $$h$$ above the earth's surface. If the body is taken to a depth $$h$$ in a mine, change in its weight is:
  • by $$0.5 \%$$ decrease
  • by $$2 \%$$ decrease
  • by $$0.5 \%$$ increase
  • by $$1 \%$$ increase
Calculate the value of $$g$$ on the surface of planet if the planet has $$1/500$$ the mass and $$1/15$$ the radius of the Earth.
  • $$0.3 m/s_2$$
  • $$1.6 m/s_2$$
  • $$2.4 m/s_2$$
  • $$4.5 m/s_2$$
  • $$7.1 m/s_2$$
An object is released from rest at a distance of $$2vr_e$$ from the center of the Earth, where $$r_e$$ is the radius of the Earth. In terms of the gravitational constant (G ), the mass of the Earth (M ), and $$r_e$$, what is the velocity of the object when it hits the Earth?
  • $$\sqrt{GM/r_e}$$
  • $$GM/r_e$$
  • $$\sqrt{GM/2r_e}$$
  • $$GM/2r_e$$
  • $$2GM/r_e$$
A person normally weighs 800N at sea level, climbs to the top of a mountain. While on top of the mountain that person will weigh:
  • Zero
  • Approximately $$800N$$
  • Considerably less than $$800N$$ but more than zero
  • Considerably more than $$800N$$
  • Need more information
A diver stands a top a platform that is $$15$$ meters high. After diving, She challenges herself from a cliff that is $$30$$ meters high. Since she is twice as far from the surface of the earth when she is on the cliff as compared with the diving board. how does her weight on the cliff compare with her weight on the diving board?
  • Her weight on the cliff is half as much.
  • Her weight on the cliff is one-fourth as much.
  • Her weight on the cliff is about the same.
  • Her weight on the cliff is twice as much.
  • Her weight on the cliff is four times as much.
Fifteen joules of work is done on object A so that only its gravitational potential energy changes. Sixty joules of work is done on object B (same mass as object A) so that only its gravitational potential energy changes.
How many times does the height of object B change compared to the height change of object A, as result of the work done?
  • Object B changes height four times as much as object A changes height
  • Object B changes height sixteen times as much as object A changes height
  • Object B changes height two times as much as object A changes height
  • Object B changes height less than two times as much as object A changes height (but not the same amount)
  • Object B changes height the same amount as object A changes height
Calculate the mass and weight of the object which is at height of twice the radius of the Earth from the surface of the Earth, if mass and weight of the object is $$m$$ and $$w$$ respectively.
  • its mass is $$\dfrac{m}{2}$$ and its weight is $$\dfrac{w}{2}$$
  • its mass is $$m$$ and its weight is $$\dfrac{w}{8}$$
  • its mass is $$\dfrac{m}{2}$$ and its weight is $$\dfrac{w}{4}$$
  • its mass is $$m$$ and its weight is $$\dfrac{w}{4}$$
  • its mass is $$m$$ and its weight is $$\dfrac{w}{9}$$
If earth were to rotate on its own axis such that the weight of a person at the equator becomes half the weight at the poles, then its time period of rotation is: ($$g$$=acceleration due to gravity near the poles and $$R$$ is the radius of earth) (Ignore equatorial bulge)
  • $$\displaystyle 2\pi \sqrt { \frac { R }{ 2g } } $$
  • $$\displaystyle 2\pi \sqrt { \frac { R }{ 3g } } $$
  • $$\displaystyle 2\pi \sqrt { \frac { R }{ g } } $$
  • $$\displaystyle 2\pi \sqrt { \frac { 2R }{ g } } $$
When a body is at a depth 'd' from the earth surface its distance from the centre of the earth is _______
  • $$(R - d)$$
  • $$2(R - d)$$
  • $$(3R - d)$$
  • $$(R - 2d)$$
How far above the earth's surface must an astronaut in space be if they are to feel a gravitational acceleration that is half what they would feel on the surface of the earth?
  • $${R}_{Earth}$$
  • $$2{R}_{Earth}$$
  • $$\dfrac{{R}_{Earth}}{2}$$
  • $$\sqrt{2}{R}_{Earth}$$
  • $$\sqrt{2}{R}_{Earth}-{R}_{Earth}$$
Every planet revolves around the sun in a/an ______ orbit.
  • elliptical
  • circular
  • parabolic
  • none of these
The ratio of SI unit of G to its CGS unit is _______.
  • $$100 : 1$$
  • $$1000 : 1$$
  • $$10 : 1$$
  • $$10000 : 1$$
An astronaut who weighs $$162$$ pounds on the surface of the earth is orbiting the earth at a height above the surface of the earth of two earth radii ($$h = 2R$$ where R is the radius of the earth.)
How much does this astronaut weigh while in orbit at this height (With how much force is the earth pulling on him while he is in orbit at this height?)
  • $$81\ pounds$$
  • $$40.5\ pounds$$
  • $$18\ pounds$$
  • $$54\ pounds$$
  • $$0\ pounds$$ (astronaut is weightless)
A body weighs $$72 N$$ on the surface of the earth. What is the gravitational force on it at a height equal to half the radius of the earth from the surface?
  • $$72 N$$
  • $$28 N$$
  • $$16 N$$
  • $$32 N$$
State whether true or false.
The value of acceleration due to gravity becomes half at a depth of half the radius of the earth.
  • True
  • False
The figure given below shows a planet in elliptical orbit around the sun $$S$$. At what position will the kinetic energy of the planet be maximum?
516610.jpg
  • $${ P }_{ 1 }$$
  • $${ P }_{ 4 }$$
  • $${ P }_{ 3 }$$
  • $${ P }_{ 2 }$$
If R is the radius of earth, the height at which the weight of a body becomes $$1/4$$ its weight on the surface of earth is :
  • $$2R$$
  • $$R$$
  • $$R/2$$
  • $$R/4$$
At what height from the surface of the earth (in terms of the radius of earth) the acceleration due to gravity will be $$\dfrac {g}{2}?$$
  • $$R\sqrt {2}$$
  • $$R(\sqrt {2} - 1)$$
  • $$R$$
  • $$R(\sqrt {2} - 2)$$
At what height from the surface of the earth (in terms of the radius of earth) the acceleration due to gravity will be $$\dfrac {4g}{9}?$$
  • $$9R/4$$
  • $$R/2$$
  • $$3R/2$$
  • $$4R/9$$
A body weighs $$100\ N$$ at a distance $$\dfrac {R}{4}$$ from centre of earth. Find its weight at height of $$9\ R$$ from the surface of earth (R - Radius of earth)
  • $$400\ N$$
  • $$3.6\ N$$
  • $$1\ N$$
  • $$4\ N$$
A body weighs $$72\ N$$ on the surface of earth. What is the gravitational force on it due to earth at a height equal to half the radius of the earth from the surface?
  • $$72\ N$$
  • $$28\ N$$
  • $$16\ N$$
  • $$32\ N$$
At a place, the 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:
  • $$64\ km$$ below the surface of the earth
  • $$64\ km$$ above the surface of the earth
  • $$30\ km$$ above the surface of the earth
  • $$32\ km$$ below the surface of the earth
A spring balance is graduated when it is at sea level. If a body is weighed at consecutively increasing heights from earth's surface, the weight indicated by the balance:
  • will go on increasing continuously
  • will go on decreasing continuously
  • will remain same
  • will first increase and then decrease
As the planet revolves from point P to point Q, the velocity of the planet :

518330_236fb54e38354904b8ec361c46f858a9.png
  • increases
  • decreases
  • remains same
  • remains equal in magnitude but opposite in direction
At what depth from the surface of the earth (in terms of the radius of earth) the acceleration due to gravity will be: $$\dfrac {2g}{5}$$?
  • $$2/5R$$
  • $$3/5R$$
  • $$4/25R$$
  • $$9/25R$$
At what height from the surface of the earth (in terms of the radius of earth) the acceleration due to gravity will be $$\dfrac {g}{100}?$$
  • $$10R$$
  • $$9R$$
  • $$100R$$
  • $$R/100$$
As the altitude increases, the acceleration due to gravity:
  • Remains constant
  • Becomes zero
  • Decreases
  • Increases
The value of universal gravitational constant $$G$$ is-
  • $$6.67\times 10^{-11} \dfrac{Nm^2}{kg}$$
  • $$6.67\times 10^{-11} \dfrac{Nm^2}{kg^2}$$
  • $$66.7\times 10^{-11} \dfrac{Nm^2}{kg^2}$$
  • $$66.7\times 10^{-11} \dfrac{Nm^2}{kg}$$
S.I. Unit of universal gravitational constant $$G$$ is-
  • $$\dfrac{Nm^2}{Kg}$$
  • $$\dfrac{Nm^2}{Kg^2}$$
  • $$\dfrac{Nm}{Kg^2}$$
  • $$\dfrac{Nm}{Kg}$$
If the radius of the earth shrinks by $$1.5$$% (mass remaining same), then the value of acceleration due to gravity changes by :
  • $$1$$%
  • $$2$$%
  • $$3$$%
  • $$4$$%
The value of g on the earth's surface is $$980\ cm\ s^{-2}$$. Its value at a height of $$64\ km$$ from the earth's surface is
  • $$960.40\ cm\ s^{-2}$$
  • $$984.90\ cm\ s^{-2}$$
  • $$982.45\ cm\ s^{-2}$$
  • $$977.55\ cm\ s^{-2}$$
Variation of acceleration due to gravity $$\left(g\right)$$ with distance $$x$$ from the centre of the earth is best represented by : ($$R \rightarrow$$ Radius of the earth)
At the centre of the earth acceleration due to gravity is:
  • zero
  • infinity
  • 9.8
  • 98
At a point very near to the earth's surface, the acceleration due to gravity is g. What will be the acceleration due to gravity at the same point if the earth suddenly shrinks to half its radius without any change in its mass?
  • $$2\ g$$
  • $$4\ g$$
  • $$g$$
  • $$3\ g$$
Dimensional formula of universal gravitational constant $$G$$ is-
  • $$M^{-1}L^3T^{-2}$$
  • $$M^{-1}L^2T^{-2}$$
  • $$M^{-2}L^3T^{-2}$$
  • $$M^{-2}L^2T^{-2}$$
The minimum speed of a particle projected from earth's surface so that it will never return is/are:
  • $$\dfrac{GM}{R}$$
  • $$22.1 km/s$$
  • $$(4g_oR)$$
  • none of above
The gravitational potential difference between the surface of a planet and a point $$20\ m$$ above it is $$16\ J/kg$$. Then the work done in moving a $$2\ kg$$ mass by $$8\ m$$ on a slope $$60$$ degree from the horizontal, is:
  • $$11.1\ J$$
  • $$5.5\ J$$
  • $$16\ J$$
  • $$27.7\ J$$
A particle hanging from a massless spring stretches it by $$2\ cm$$ at earth's surface. How much will the same particle stretch the spring at height $$2624\ km$$ from the surface of earth? ( Radius of earth $$=6400\ km$$)
  • $$1\ cm$$
  • $$2\ cm$$
  • $$3\ cm$$
  • $$4\ cm$$
If earth's radius were to hypothetically shrink by $$1\%$$, the value of $$G$$ would:
  • Shrink by $$1\%$$
  • Expand by $$1\%$$
  • Remain the same
  • Shrink by $$0.01\%$$
The SI unit of gravitational potential is
  • $$J$$
  • $$Jkg^{-1}$$
  • $$Jkg$$
  • $$Jkg^{-2}$$
How the gravitational constant will change if a brass plate is introduced between two bodies?
  • No change
  • Decreases
  • Increases
  • No sufficient data
The minimum energy required to launch a $$m$$ kg satellite from earth's surface in a circular orbit at an altitude of $$2R$$ where $$R$$ is the radius of earth, will be:
  • $$3mgR$$
  • $$\dfrac{5}{6} mgR$$
  • $$2mgR$$
  • $$\dfrac{1}{5} mgR$$
Let $$V$$ and $$E$$ be the gravitational potential and gravitational field at a distance $$r$$ from the centre of a uniform spherical shell. Consider the following two statements, ($$A$$) The plot of $$V$$ against $$r$$ is discontinuous and ($$B$$) The plot of $$E$$ against $$r$$ is discontinuous.
  • Both A and B are correct
  • A is correct but B is wrong
  • B is correct but A is wrong
  • both A and B are wrong.
 If a particle is slowly brought from reference point to another point $$P$$ in a gravitational field, then work done per unit mass by the external agent is (at that point)
  • gravitational force
  • gravitational field intensity
  • gravitation potential
  • none of the above
A body of mass 'm' is approaching towards the centre of a hypothetical hollow planet of mass 'M' and radius 'R'. The speed of the body when it passes the centre of the planet through a diametrical tunnel is:
  • $$\sqrt {\dfrac{GM}{R}}$$
  • $$\sqrt {\dfrac{2GM}{R}}$$
  • Zero
  • none of these.
 The value of g at a particular point is 9.8 $$m/sec^2$$ 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
  • $$9.8m/sec^2$$
  • $$4.9m/sec^2$$
  • $$19.6m/sec^2$$
  • $$3.1m/sec^2$$
The energy required to remove a body of mass $$m$$ from earth's surface is/are equal to:
  • $$\dfrac{-GMm}{R}$$
  • $$mgR$$
  • $$-mgR$$
  • none of these.
A hypothetical planet has density $$\rho$$, radius R, and surface gravitational acceleration g. If the radius of the planet were doubled, but the planetary density stayed the same, the acceleration due to gravity at the planet's surface would be.
  • $$4g$$
  • $$2g$$
  • g
  • $$g/2$$
The minimum speed of a particle projected from earths surface so that it will never return is/are:
  • (GM/R)
  • 22.1 km/sec
  • $$(4g_oR)$$
  • none of above
The value of acceleration due to gravity at a depth of $$1600 km$$ is equal to [Radius of earth $$= 6400 km$$]
  • $$9.8{ ms }^{ -2 }$$
  • $$4.9{ ms }^{ -2 }$$
  • $$7.35{ ms }^{ -2 }$$
  • $$19.6{ ms }^{ -2 }$$
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