Which of the following particles will trace out the smallest circle if projected with identical velocity perpendicular to a magnetic field?

Step-by-step solution

The radius of the circular path of a charged particle moving perpendicular to a uniform magnetic field is given by r = mv qB . Since the velocity v and the magnetic field B are identical for all the given particles, the radius r is directly proportional to the mass-to-charge ratio m q . For the given particles, the magnitude of the charge q is the same (equal to e ). Thus, the radius is directly proportional to the mass of the particle ( r m ). Among He ^+ , Li ^+ , electron, and proton, the electron has the smalle