Gravitation - Quiz 13

GRAVITATION QUIZ-13

Dear Readers,

JEE Advanced Physics Syllabus can be referred by the IIT aspirants to get a detailed list of all topics that are important in cracking the entrance examination. JEE Advanced syllabus for Physics has been designed in such a way that it offers very practical and application-based learning to further make it easier for students to understand every concept or topic by correlating it with day-to-day experiences. In comparison to the other two subjects, the syllabus of JEE Advanced for physics is developed in such a way so as to test the deep understanding and application of concepts.

Gravitation is an easy to understand and a highly scoring topic. It might have a 1% weightage in the entire JEE Physics portion but do not neglect. You can practice these questions on regular basis to know what are the important points to remember at the moment when gravitation question comes.

Q1.A solid sphere of uniform density and radius R applies a gravitational force of attraction equal to F₁ on a particle placed at a distance 2R from the centre of the sphere. A spherical cavity of radius R/2 is now made in the sphere as shown in the figure. The sphere with the cavity now applies a gravitational force F₂ on the same particle. The ratio F₁/F₂ is

•  1/2
•  3/4
•  7/8
•  9/7

Solution

Q2.The given figure shows the motion of a planet around the Sun S in an elliptical orbit with the Sun at the focus. The shaded areas A and B are also shown in the figure which can be assumed to be equal. If t₁ and t₂ represent the time taken for the planet to move from a to b and c to d, respectively, then

•  t₁ < t₂
•  t₁>t₂
•  2t₁=t₂
•  From the given information the relation between t₁ and t₂ cannot be determined

Solution

Q3.Imagine a light planet revolving around a very massive star in a circular orbit of radius R with a speed of revolution T. If the gravitational force of attraction between the planet and the star is proportional to R^-2.5, then

•  T² is proportional to R²
•  T² is proportional to R^3.5
•  T² is proportional to R^1.5
•  T² is proportional to R^3.75

Solution

Q4.The atmosphere is held to the earth by

•  Winds
•  Gravity
•  Clouds
•  None of the above

Q5.Two spherical bodies of masses m and 5M and radii R and 2R, respectively, are released in free space with initial separation between their centres equal to 12R. If they attract each other due to gravitational force only, then the distance covered by the smaller body just before collision is

•  2.5 R
•  4.5 R
•  7.5 R
•  1.5 R

Solution

Q6.If three uniform spheres, each having mass M and radius R, are kept in such a way that each touches the other two, the magnitude of the gravitational force on any sphere due to the other two is

•  (GM²)/(4r² )
•  0.1(2GM²)/r²
•  (2GM²)/(4r²)
•  (√3 GM²)/(4r² )

Solution

Q7.Suppose that the acceleration of a free fall at the surface of a distant planet was found to be equal to that at the surface of the earth. If the diameter of the planet were twice the diameter of the earth, then the ratio of mean density of the planet to that of the earth would be

•  4:1
•  2:1
•  1:1
•  1:2

Solution