Question

Determine $e/m$ for proton ($e$ = charge, $m$ = mass):
A. Less than $e/m$ value of electron
B. Equal to $e/m$ value of electron
C. Greater than $e/m$ value of electron
D. All the above.

Answer 1

Proton consists of the nucleus of an atom. The nucleus is responsible for the mass of an atom. The mass of a proton is more than an electron.

Complete step by step answer:
The numerical value of the charge is the same for both the proton and electron, i.e. $1$. The magnitude of charge is positive for protons and negative for electrons. The mass of a proton is $1836$ times the mass of an electron.
The proton has mass very much greater than the mass of an electron. The value of $e/m$ for protons is lower compared to the value of electrons. Actually the $e/m$ ​for an electron is $1836$ times the $e/m$ for a proton.

Hence option A is the correct answer, i.e. less than $e/m$ value of electron.

Additional Information:
It was Robert Millikan who won the Nobel prize in physics in $1923$ for the discovery of charge of electrons. Then as American physicist R. Millikan in $1909$ measured the charge of an electron using negatively charged oil droplets. The charge (e) of an electron is measured as $- 1.60 \times {10^{ - 19}}Coulombs$. The mass of electron was found by J J Thomas and the value is $9.1{\text{ }}x{10^{ - 31}}kg$.
It was Ernest Rutherford in $1911$ who discovered charge of a proton to be one positive unit. The mass of the proton was found to be $1.67x{10^{ - 27}}kg$.

Note:
The nucleus of the atom consists of protons and neutrons. The mass of an atom is responsible for the nucleus of the atom. The charge of an element is neutral due to cancellation of equal positive and negative charge. The neutron carries no net charge.