A proton, a deutron and an `alpha`-particle having the same momentum, enters a region of uniform electric field between the parallel plates of a capacitor. The electric field is perpendicular to the initial path of the particles. Then the ratio of deflections suffered by them is

Options

A. `1: 2 : 8`
B. `1 : 2 : 4`
C. `1 : 1 : 2`
D. None of these

Answer

A

Explanation

Deflection suffered by charged particle in an electric field
`y prop (qm)/p^2`
As `m_p : m_d : m_(alpha) = 1:2:4`
And `q_p : q_d : q_(alpha) = 1:1:2`
`:. y_p : y_d : y_(alpha) = 1:2:8` (here `p_(alpha) = p_d = p_p` )