11.
The centre of gravity of a sprinter during the race lies

12.
Who enunciated the laws of planetary motion?

13.
The tidal waves on sea is mainly due to

14.
The time period of a pendulum when taken to the Moon would:

16.
The mass of a star is two times the mass of the Sun. How it will come to an end ?

17.
Which of the following celestial bodies contains abundant quantities of helium-3, a potential source of energy ?

18.
The period of revolution of a certain planet in an orbit of radius R is T. Its period of revolution in an orbit of radius 4R will be:

19.
Which is evidence that supports the dynamo theory?

20.
Which of the following is indicated by the colour of a star ?