Electrons accelerated by a potential differnece V enter a uniform magnetic field of flux density B at right angles to the field. They describe a circular path of radius `'r'`. If now `'V'` is doubled and B is also doubled, the radius of the new circular path is

Options

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

Answer

4

Explanation

`(r_(1))/(r_(2))=sqrt((v_(1))/(v_(2))xx(B_(2)^(2))/(B_(1)^(2)))`