Question

The radii of two planets are R and 2R respectively and their densities P and P/2 respectively. What is the ratio of acceleration due to gravity at their surfaces ?

Answer 1

acc due to gravity at the surface of planet = g = (4/3) GRλp

Planet 1; R = R
p = P

so, 
g1 = (4/3) GRλP

planet 2 ; R = 2R
p = P/2
so, 
g2 = (4/3) G2RλP/2
or 
g2 = (4/3) GRλP

thus g1 = g2
ratio will be 1:1

Answer 2

heya ..........

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