A Level Physics Practice Exam

What is the energy of an electron that moves through a potential difference of 2000V?

1. 2000J

2. 2000eV

3. 2000kJ

4. 2000mV

The correct answer is: 2000eV

The energy gained by an electron when it moves through a potential difference can be calculated using the relationship between electric potential and kinetic energy. When an electron moves through a potential difference (voltage), it receives energy equal to the charge of the electron multiplied by the potential difference it traverses. The charge of an electron is approximately \(1.6 \times 10^{-19}\) coulombs. When the electron moves through a potential difference of 2000 volts, the energy gained can be calculated using the equation: \[ \text{Energy (in joules)} = \text{Charge (in coulombs)} \times \text{Potential difference (in volts)} \] Substituting the known values, we have: \[ \text{Energy} = (1.6 \times 10^{-19} \, \text{C}) \times (2000 \, \text{V}) = 3.2 \times 10^{-16} \, \text{J} \] This energy can also be expressed in electronvolts (eV), where 1 eV is defined as the amount of energy gained by an electron when it moves through a potential difference of 1 volt. Hence, moving through