The law of gravitation was given by :

1. Thomas Alva Edison
2. Alexander Graham Bell
3. Sir Isaac Newton
4. Albert Einstein

The forces of attraction acting between two bodies is :

1. directly proportional to the product of their masses
2. directly proportional to the square of the distance between them
3. inversely proportional to the square of the distance between them
4. both (a) and (c)

The value of G is —

1. 9.8 N m² kg^-2
2. 6.7 x 10^-11 N m² kg^-2
3. 6.7 x 10^-11 m s^-2
4. 6.7 N kg^-1

The value of gravitational constant G changes with the change in :

1. height
2. place
3. distance
4. it remains unchanged