Question

The energy of electron is 2.5 eV. When expressed in Joule, it is ______.

Options

• \[1.6 \times 10^{-19}\] J

• \[4.0 \times 10^{-19}\] J

• \[3.2 \times 10^{-19}\] J

• 0

Answer 1

The energy of electron is 2.5 eV. When expressed in Joule, it is \[\mathbf{\underline{4.0 \times 10^{-19}J}}\].

Explanation:

Since \[1\text{ eV} = 1.6 \times 10^{-19}\text{ J}\], \[2.5\text{ eV} = 2.5 \times 1.6 \times 10^{-19} = 4.0 \times 10^{-19}\text{ J}\].