The escape velocity from the earth is about 11 km/s. The escape velocity from a planet having twice the radius and the twice mean density as the earth, is

Options

A. `22 kms ^(-1)`
B. `11 km s ^(-1)`
C. `5.5 km s ^(-1)`
D. `15.5 km s ^(-1)`

Answer

A

Explanation

The escape velocity can be given by
`v = sqrt (( 2 GM )/( R )) = sqrt ( 2 G ( 4)/(3) pi R ^(2) d )`
` v prop R sqrt d `
Hence escape velocity from the other planet is,
`v . = 2 v _(0)`