What is a Black Hole?
A deep hole in the Sun
Space between two planets
A massive dead star
A huge planet
The dead star which has a tendency of engulfing the whole planet if nearby due to its gravitation is called Black Hole.
Imagine a planet is revolving around a very massive star in a circular orbit of radius R with a period of revolution T. If the gravitational force of attraction between the planet and the star is proportional to R−52, then
A small planet is revolving with a speed v around a very massive star in a circular orbit of radius r with a revolution period T. If the gravitational force between the planet and the star were inversely proportional to r, then,