The energy of an electron is 4.0 `xx10^(-19)` J.Express it in eV.

Explanation

To convert the energy of an electron from joules to electron volts, we can follow these steps:

### Step 1: Understand the definition of an electron volt (eV)
1 electron volt (eV) is defined as the amount of energy gained by an electron when it is accelerated through a potential difference of 1 volt. In terms of joules, 1 eV is equal to \( 1.6 \times 10^{-19} \) joules.

### Step 2: Write down the given energy in joules
The energy of the electron is given as:
\[ E = 4.0 \times 10^{-19} \text{ J} \]
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