Statement (A) Two artificial satellites revolving in the same circular orbit have same period of revolution.

Statement (B) The orbital velocity is inversely proportional to the square root of radius of the orbit.

Statement (C) The escape velocity of the body is independent of the altitude of the point of projection.

A uniform solid sphere of radius $$R$$ produces a gravitational acceleration of $$a_0$$ on its surface. The distance of the point from the centre of the sphere where the gravitational acceleration becomes $$\frac{a_0}{4}$$ is

A projectile is thrown straight upward from the earth's surface with an initial speed $$v=\alpha v_e$$ where $$\alpha$$ is a constant and $$v_e$$ is the escape speed. The projectile travels upto a height 800 km from earth's surface, before it comes to rest. The value of the constant $$\alpha$$ is (radius of the earth $$=6400 \mathrm{~km}$$)