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Grade 99 grade science

The mean distance of two planet a and b from the sun is 2 and 4 times the distance of earth from the sun respectively. Find the ratio of the time taken by the two planets to make one revolution around the sun.

Profile image of Judhisthir Behera
7 Years agoGrade 9
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2 Answers

Profile image of Arun
7 Years ago
 
As we know,
From kepler law,
T^2= k* r^3
 
Hence
(T1/T2)^2 = (r1/r2)^3
(T1/T2)^2  = (2r/4r)^3
T1/T2 = \sqrt(1/8)
T1/T2 = 1/2\sqrt2
Profile image of Sayantan Garai
7 Years ago
From Kepler's law,
T²αR³
Hence,
(T1/T2)²=(R1/R2
=> T1/T2=√(1/2)³
                 =√(1/8)
=1 / 2√2
=√2 / 4
Hence answer is 1:2√2 or √2:4.