A mass of `6xx10^(24) kg` is to be compressed in a sphere in such a way that the escape velocity from its surface is `3xx10^(8) m//s`. Find the radius of the sphere (in `mm`).

Options

A. 9 mm
B. 8 mm
C. 7 mm
D. 6 mm

Answer

B

Explanation

As, `v_(e)=sqrt(((2"GM")/("R"))),R=((2"GM")/(v_(e)^(2)))`,
`:.R=(2xx6.67xx10^(-11)xx6xx10^(24))/((3xx10^(8))^(2))`
`=9xx10^(-3)m=9" mm"`