The radii of two planets are respectively

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The radii of two planets are respectively ${R_1}$ and ${R_2}$ and their densities are respectively ${\rho _1}$ and ${\rho _2}$. The ratio of the accelerations due to gravity at their surfaces is

A

${g_1}:{g_2} = \frac{{{\rho _1}}}{{R_1^2}}:\frac{{{\rho _2}}}{{R_2^2}}$

B

${g_1}:{g_2} = {R_1}{R_2}:{\rho _1}{\rho _2}$

C

${g_1}:{g_2} = {R_1}{\rho _2}:{R_2}{\rho _1}$

D

${g_1}:{g_2} = {R_1}{\rho _1}:{R_2}{\rho _2}$

The radii of two planets are respectively ${R_1}$ and ${R_2}$ and their densities are respectively ${\rho _1}$ and ${\rho _2}$. The ratio of the accelerations due to gravity at their surfaces is

$g = \frac{4}{3}\pi \rho GR$

$\therefore \frac{{{g_1}}}{{{g_2}}} = \frac{{{R_1}{\rho _1}}}{{{R_2}{\rho _2}}}$