An electron enters into the space of uniform field of finite width making an angle `60^(@)` to the field lines and leaves at angle `30^(@)` to the field lines. The ratio of its kinetic energy while entering the electric field to the while leave will be :

Options

A. `(1)/(3)`
B. `sqrt((3)/(1))`
C. `(2)/(3)`
D. `3`

Answer

A

Explanation

`K_(1)=(1)/(2)mV_(0)^(2)(1+(1)/(3))`
`K_(2) =(1)/(2)mV_(0)^(2)(1+3)`
`(K_(1))/(K_(2))=(1)/(3)`