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

Options

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

Answer

C

Explanation

`F=Bqv,` But `1/2 mv^(2)=ev` or `v=sqrt((2ev)/m):.F=Bqsqrt((2eV)/m)`
`implies F prop sqrt(v)` and `F'prop sqrt(2V), (F')/F=sqrt(2)` or `F'=sqrt(2)F`