Question

The increasing order for the magnitude of e/m (charge/mass) for an electron (e), proton (p), neutron (n) and an alpha-particle ($\alpha$) is:

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

Answer 1

The correct option is C n < $\alpha$ < p < e

An electron and a proton have the same magnitude of charge. A neutron has no charge. An alpha particle has a charge double that of a proton i.e. charge of 2 protons and 4 times the mass of a proton.
So, the order of increasing e/m ratio is: n < $\alpha$ < p < e