Question

Increasing order (lowest first) for the values of $e/m$ (charge / mass) for electron $\left(e\right)$, proton $\left(p\right)$, neutron $\left(n\right)$ and $\alpha$-particle $\left(\alpha \right)$ is:

• A. $e,p,n,\alpha$
• B. $n,p,e,\alpha$
• C. $n,p,\alpha ,e$
• D. $n,\alpha ,p,e$

Answer 1

The correct option is D $n,\alpha ,p,e$

Increasing order (lowest first) for the values of e/m (charge / mass) for electron (e), proton (p), neutron (n) and α-particle (α) is $n,\alpha ,p,e$
e/m for neutron $=\frac{0}{1}=0$
e/m for alpha particle $=\frac{2}{4}=0.5$
e/m for proton $=\frac{1}{1}=1$
e/m for electron $=\frac{1}{\left(\frac{1}{1850}\right)}=1850$
Note: e is the charge of the particle, m is the mass of a particle and the mass of an electron is $\frac{1}{1850}$ times the mass of proton.

Hence, the correct option is $D$