A beam of alpha particles and of the protons of the same velocity V, enter a uniform magnetic field at right angles to the field lines. The particles describe circular paths. What is the ratio of the radii of these two circles?

Explanation

Using, `r=(mv)/(Bq)`
For proton, `r=(mV)/(Bq)`
and for alpha particle, `r.=(4mV)/(B(2q))`
`therefore r/(r.)=1/2`