Question

Two charged particles M and N enter a region of uniform magnetic field with velocities perpendicular to the field. The paths of particles are shown in figure. The possible reason is

• A. The charge of M is greater than that of N
• B. The momentum of M is greater than that of N
• C. The charge to mass ratio of M is greater than that of N
• D. The speed of M is greater than that of N

Answer 1

The correct option is C The charge to mass ratio of M is greater than that of N

The radius of the circular path of a particle of mass m, charge e moving with a speed υ perpendicular to a magnetic field B is given by
$\frac{m{v}^2}{r}=evB$ or $r=\left(\frac{m}{e}\right)\frac{v}{B}$
Thus, r is inversely proportional to $\left(\frac{e}{m}\right)$, the charge to mass ratio.