A satellite is revolving round the earth in circular orbit, which of the following is true ?

1. if mass of earth is made four times, keeping other factors constant, orbital speed of satellite will become two times
2. corresponding to change in part(a), times period of satellite will remain half 
3. when value of G is made two times orbital speed increases and time period decreases 
4. G has no effect on orbital speed and time period and time period

(1), (2) and (3)

\(v \propto \sqrt{m}\)

\(v_2 = 2 v_1\) 

\(\Rightarrow T \propto \frac{1}{v}\)

\(\Rightarrow T_2 = \frac{1}{2} T_1\)

as \(v \propto \sqrt{G}\) so wth increase in G, v increase and T decreases.