Question

Find the ratio of $\frac{e}{m}$ of an alpha particle to to that of a neutron.

• A. $0$
• B. $\infty$
• C. $1$
• D. $2$

Answer 1

The correct option is B $\infty$

Alpha particle is identical to the nucleus of Helium-4 atom.
Charge on alpha particle = 2e
Mass of alpha particle = 4$m_p$
where $m_p$ = mass of proton
$\frac{e}{m}$ = $\frac{2e}{4m_p}$ = $\frac{e}{2m_p}$
Charge on neutron is zero
So, $\frac{e}{m}$ = 0
Therefore, $\frac{(\frac{e}{m}{)}_{alphaparticle}}{\left(\frac{e}{m}\right)neutron}=\frac{0.5}{0}=\infty$