Q. An $\alpha$ particle and a proton travel with same velocity in a magnetic field perpendicular to the direction of their velocities. Find the ratio of the radii of their circular path
A) $4\ :1$
B) $1\ :4$
C) $2\ :1$
D) $1\ :2$
Explanation
(c) $r = \frac{mv}{qB} \Rightarrow \frac{r_{\alpha}}{r_{p}} = \frac{m_{\alpha}}{m_{p}} \times \frac{q_{p}}{q_{\alpha}} = \frac{4}{1} \times \frac{1}{2} = \frac{2}{1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.