One electron volt is equal to ______
a)$1.6\times {{10}^{-19}}\text{ Joule}$
b)$16\times {{10}^{-19}}\text{ Joule}$
c)$1.6\times {{10}^{-10}}\text{ Joule}$
d)$1.6\times {{10}^{-9}}\text{ Joule}$

Hint: According to its definition, an electron volt is the amount of kinetic energy gained by a single electron accelerating from rest through an electric potential difference of one volt in vacuum. Using this relation, find the amount of kinetic energy in joules.

Complete step by step answer:As the definition states that: Electron volt amount of kinetic energy gained by a single electron.
So, we can say that: $E=qV$, where E is kinetic energy, q is charge of electron and V is volt.
For $q=1.6\times {{10}^{-19}}C$ and $V=1V$, we get:
$E=1.6\times {{10}^{-19}}J$
Therefore, option (a) is the correct answer.

Note:It is a common unit of energy within physics, widely used in solid state, atomic, nuclear, and particle physics. It is commonly used with the metric prefixes milli-, kilo-, mega-, giga-, tera-, peta- or exa- (meV, keV, MeV, GeV, TeV, PeV and EeV respectively). In some older documents, and in the name Bevatron, the symbol BeV is used, which stands for billion (109) electrinos; it is equivalent to the GeV.
Electron volt and Volt are two different units. Electron volt is a unit of energy. Whereas volt is the SI unit of electric potential, potential difference or e.m.f. (electromotive force). It may help to realize that the electric potential is a property associated with the field in the space while the energy is associated with the particle you place into that field