An electron accelerated through a potential difference V passes through a uniform transverse magnetic field and experiences a force F. If the accelerating potential is increased to 2V, the electron in the same field will experience a force

Options

A. F
B. `F//2`
C. `sqrt 2 F`
D. 2F

Answer

c

Explanation

`F=Bqv`
But `1/2mv^2=eV or v=sqrt((2eV)/m)`
`:. F=(Bq)sqrt((2eV)/m)`
`implies Fprop sqrtV and`
`F'prop sqrt2V`
`(F')/(F)=sqrt(2)` or `F'=sqrt2F`.