The diameters of two planets are in ratio $4:1$ . Their mean densities have ratio $1:2$ . The ratio of gravitational acceleration on the surface of planets will be

A body weighs $700 \,gm$ wt on the surface of the earth. How much will it weigh on the surface of a planet whose mass is $\frac{1}{7}$ and radius is half that of the earth …….. $gm\, wt$

If the value of g at the surface of the earth is $9.8$ $m/{\sec ^2}$, then the value of g at a place $480\, km$ above the surface of the earth will be ………. $m/{\sec ^2}$. (Radius of the earth is $6400\, km$)   

The approximate height from the surface of earth at which the weight of the body becomes $\frac{1}{3}$ of its weight on the surface of earth is $……….km$ : [Radius of earth $R =6400 \,km$ and $\sqrt{3}=1.732]$

If radius of the earth is $6347\, km ,$ then what will be difference between acceleration of free fall and acceleration due to gravity near the earth's surface ?