Gravitation (NEET (NTANational Eligibility cum Medical Entrance Test) Physics): Questions 20  24 of 84
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Question number: 20
» Gravitation » Gravitational Acceleration
Question
Two planets of radii in the ratio 1: 2 are made from the materials of density in the ratio 3: 1. Then the ratio of acceleration due to gravity g _{1} /g _{2} at the surface of two planets will be
Choices
Choice (4)  Response  

a. 


b. 


c. 


d.  1 

Question number: 21
» Gravitation » Energy
Assertion (Ꭺ)
If an earth satellite moves to a lower orbit, there is some dissipation of energy but the speed of gravitational satellite increases.
Reason (Ꭱ)
The speed of satellite is a constant quantity.
Choices
Choice (4)  Response  

a.  Ꭺ is true but Ꭱ is false 

b.  Ꭺ is false but Ꭱ is true 

c.  Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ 

d.  Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ 

Question number: 22
» Gravitation » Kepler's Laws of Planetary Motion
Question
The Jupiter’s period of revolution round the Sun is 12 times that of the Earth. Assuming the planetary orbits are circular, how many times the distance between the Jupiter and Sun exceeds that between the Earth and the sun.
Choices
Choice (4)  Response  

a.  5.242 

b.  3.242 

c.  2.242 

d.  4.242 

Question number: 23
» Gravitation » GeoStationary Satellites
Question
The moon revolves round the earth 13 times in one year. If the ratio of sunearth distance to earthmoon distance is 393, then the ratio of masses of sun and earth will be –
Choices
Choice (4)  Response  

a.  356 

b.  365 

c.  1 

d.  3.56 ⨯ 10 ^{5} 

Question number: 24
» Gravitation » Orbital Velocity of a Satellite
Question
A satellite is revolving in an orbit close to the earth’s surface. Taking the radius of the earth as 6.4 ⨯ 10 ^{6} meter, the value of the orbital speed and the period of revolution of the satellite will respectively be (g = 9.8 meter/sec ^{2})
Choices
Choice (4)  Response  

a.  7.2 km/sec, 8.6 minutes 

b.  7.2 km/sec, 84.6 minutes 

c.  0.72 km/sec, 84.6 minutes 

d.  2.7 km/sec, 8.6 minutes 
