A star is bieng orbited by a planet P such that the planet rotates around itself once every 0.1 earth days. It is observed that P completes 196 rotations around itself by the time it completes 1 revolution around S. If the planet's sense of rotation and revolution is in same direction,its orbital period (in rarth days) would be 
 
(A) 19.6            (B)  19.5         (C)  19.7          (D)19.8

Asked by chandubeats21 | 17th May, 2017, 06:52: PM

Expert Answer:

The rotation period of the star is 0.1 Earth days = 0.1 × 24 = 2.4 hrs
 
The star completes 196 rotations for 1 revolution around the star S.
 
So, the revolution period with respect to Earth hours is 196 × 2.4 = 470.4 hours
 
Now, if one Earth day is 24 hours long, then the revolution period w.r.t Earth days is
 
begin mathsize 12px style fraction numerator 470.4 over denominator 24 end fraction equals 19.6 Earth space days end style

Answered by Romal Bhansali | 19th May, 2017, 10:00: AM

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