NEET UG Physics Gravitational MCQs

35. At what height over the earth’s pole, the free fall acceleration decreases by one percent = ______ km (Re = 6400 km).
(A) 32 (B) 80 (C) 1.253 (D) 64

36. Weight of a body is maximum at
(A) moon (B) poles of earth (C) Equator of earth (D) Center of earth

37. At what distance from the center of earth, the value of aceeleration due to gravity g will be half that of the surfaces (R = Radius of earth)
(A) 2R (B) R (C) 1.414 R (D) o.414 R

42. Weight of 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
(A) 2% decreases (B) 0.5% decreases
(C) 1% increases (D) 0.5% increases

43. If density of earth increased 4 times and its radius becomes half of then out weight will be____
(A) Four times it present calue (B) doubled
(C) Remain same (D) halved

44. A man can jump to a height of 1.5 m on a planet A what is the height ne may be able to jump on another planet whose density and radius are respectively one- quater and one- third that of planet A
(A) 1.5 m (B) 15 m (C) 18 m (D) 28 m

45. If the value of ‘g’ acceleration due to gravity, at earth surface fis 10ms^–2. its value in ms^–2 at the center of earth, which is assumed to be a sphere of Radius ‘R’ meter and uniform density is
(A) 5 (B) 10/R (C) 10/2R (D) zero

46. A research satellite of mass 200 kg. circles the earth in an orbit of avrage radius 3R/2 where R is radius of earth. Assuming the gravitational pull 10 N, the pull on the satellite will be = _____ N
(A) 880 (B) 889 (C) 890 (D) 892

98. As astronaut orbiting the earth in a circular orbit 120 km above the surface of earth,gently drops a spoon out of space-ship. The spoon will
(A) Fall vertically down to the earth
(B) move towards the moon
(C) Will move along with sapace - ship
(D) Will move in an irregualr way then fall down to earth

99. The period of a satellite in cirular orbit around a planet is independent of
(A) the mass of the planet
(B) the radius of the planet
(C) mass of the satellite
 (D) all the three parameters (A), (B) and (C)

100. Two satellites A and B go round a planet p in circular orbits having radii 4 R and R respectively if the speed of the satellite A is 3V, the speed if satellite B will be
(A) 12V
 (B) 6V
(C) 4/3 V
(D) 3/2 V

101. A small satellite is revolveing near earth’s surface. Its orbital velocity will be nearly =_______kms^–1.
(A) 8
(B) 4
 (C) 6
(D) 11.2

102. A satellite revolves around the earth in an elliptical orbit. Its speed
(A) is the same at all points in the orbit
(B) is greatest when it is closest to the earth
(C) is greatest when it is farthest to the earth
(D) goes on increasing or decresing continuously depending upon the mass of the satellite

104 A satellite is moving around the earth with speed v in a circular orbit of radius r. If the orbit radius is decreasd by 1% its speed will
(A) increase by 1% (B) increase by 0.5%
(C) decrrease by 1% (C) Decrrease by 0.5%

105. Orbital velocity of an artifiicial satellite does not depend upon
(A) mass of earth (B) mass of satellite
(C) radius of earth (D) acceleration due to gravity

106. orbital velocity of eath’s satellite near the surface is 7 kms^–1. when the radius of orbit is 4 times that of earth’s radius, then orbital velocity in that orbit is = _____ kms^-1
(A) 3.5 (B) 17 (C) 14 (D) 35

107. Two identical satellites are at R and 7R away from each surface, the wrong statement is(R - Radius of earth)
(A) ratio of total energy will be 4
(B) ratio of kinetic energes will be 4
(C) ratio of potential energies will be 4
(D) ratio of total energy will be 4 but ratio of potential and kinetic energies will be 2

108. Which one of follwoing sttements regarding artificial satellite of earth is incorrect
(A) The orbital velocity depends on the mass of the satellite
(B) A minimum velocity of 8kms^-1 is required by a satellite to orbit quite close to the earth.
(C) The period of revolution is large if the radius of its orbit is large
(D) The height of geostationary satellite is about 36000 km from earth

109. The weight of an astronuat, in an artificial satellite revolving around the earth is
(A) zero
(B) Equal to that on the earth
(C) more than that on earth
(D) less than that on the earth

110. The distance of a geo-stationary satellite from the center of the earth (Radius R= 6400km) is nearest to
(A) 5R (B) 7R (C) 10R (D) 18R

116. When a satellite going round the earth in a circular obrit of radius r and speed v loses some of its energy, then r and v changes as
(A) r and v bothe will increase
(B) r and v both will decease
(C) r will decrease and v will increase
(D) r will increase and v will decrease

117. The time period of a satellite of earth is 5 hours If the sepration between the earth and the satellite is increased to four times the previous value, the new time period will become ____ hours
(A) 10 (B) 120 (C) 40 (D) 80

118. A person sitting in a chair in a satellite feels weightless because
(A) the earth does not attract the objects in a satellite
(B) the normal force by the chair on the person balances the earth’s attraction
(C) the normal force is zero
(D) the person in satellite is not accelerated

119. Two satellites A and B go round a planet in cirular orbits having radii 4R and R respectively If the speed of satellite A is 3v, then speed of satellite B is
(A) 3v/2 (B) 4v/2 (C) 6v (D) 12v

120. A satellite moves in a circle around the earth, the radius of this circlr is equal to one half of the radius of the moon’s orbit the satellite completes one revolution in _____ lunar month
(A) 1/2 (B) 2/3 (C) 2^–3/2 (D) 12^3/2

Assertion - Reason Type Questions

Direction (Read the following uestions and choose)

(A) If both Assertion and Reason are true and the Reason is correct explanation of assertion

(B) If both Assertion and Reason are true, but reason is not correcte explanation of the Assertion

(C) If Assertion is true, but the Reason is false

(D) If Assertion is false, but the Reason is true

Assertion - Reason Type question Answers

1. A Both the asseration and reason are true and the latter is correct expalnation of the former.

2. A Both the asseration and reason are true and the latter is correct expalnation of the former.

3. A As the satellite is to be stationary over a particular place, its time period of revolution = 24 hours= time peroid of revolution of earth about its axis.

 

 

7. A Both the asseration and reason are correct and the Reason is correct explanation of Asseration

8. A A Both the asseration and reason are correct and the Reason is correct explanation of Asseration

9. C Here Asseration is correct but Reason is wrong because the space ship while entering the earth’s atmosphere may catch fire due to atmoshperic air friction

10. D Here Both the asseration and reason are wrong because the angular momentum of earth moon system is conserved in the absence of extermal touque.