The escape velocity of a body from earth's surface is `v_e`. The escape velocity of the same body from a height equal to `7R` from earth's surface will be

Options

A. `(V_(e))/(sqrt(2))`
B. `(V_(e))/2`
C. `(V_(e))/(2sqrt(2))`
D. `(V_(e))/4`

Answer

C

Explanation

`v_(e)=sqrt((2GM)/R)`
at height `v_(e)^(1)=sqrt((2GM)/(R+h))=sqrt((2GM)/(R+7R))`