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 Fig. 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 $\nu$ perpendicular to a magnetic field B is given by
$\frac{m{\nu }^2}{r}=e\nu Borr=\left(\frac{m}{e}\right)\frac{\nu }{B}$
Thus, r is inversely proportional to $\left(\frac{e}{m}\right)$, the charge to mass ratio. Hence the correct choice is (c).