Question

One electron volt is equal to

• A. $1.6\times {10}^{-17}J$
• B. $1.6\times {10}^{-19}J$
• C. $1.6\times {10}^{-10}J$
• D. $6.1\times {10}^{-19}J$

Answer 1

The correct option is B

$1.6\times {10}^{-19}J$

Explanation

1. 1 eV is defined as the energy gained by an electron when it has been accelerated by a potential difference of 1 volt.
2. The fundamental value of the charge is $e=1.6\times {10}^{-19}\text{C}$
3. 1 eV in terms of Joule is $1eV=1.6\times {10}^{-19}\text{C-volts}=1.6\times {10}^{-19}\text{J}$

Hence, option B is the correct answer.