Q 11-07-150JEE MainJEE Main 2021 (20 Jul, Shift 2)Easy
Consider a binary star system of star $A$ and star $B$ with masses $m_A$ and $m_B$ revolving in a circular orbit of radii $r_A$ and $r_B$, respectively. If $T_A$ and $T_B$ are the time period of star $A$ and star $B$, respectively, then:
Answer: (B) $T_A = T_B$
Both stars revolve about their common centre of mass and always stay on opposite sides of it, so they have the same angular velocity and hence the same period: $T_A = T_B$.
Solution by Sreeraj P, M.Sc Physics