Question

An alpha particle have same velocity as like as proton so calcualtr is radii ratio

Answer 1

Alpha particle will be helium nucleus of charge 2e and mass 4u. Proton will be hydrogen of charge 1e and mass 1u. Radius of circle of charged particle in magnetic field will be r=mv/qb

By lorentz force,

Radius=momemtum /charge *magnetic field.

We know that radius is inversely proportional to charge. So, Radius of alpha particle will be half of radius of proton.

Hence Radii =1:2