*Question T6A04:
What electrical component stores energy in an electric field?*  

*Correct Answer is  B: Capacitor*  

### AI Response: (may contain errors)  

The correct answer is **B: Capacitor**.

### Explanation of the Correct Answer:
- A **capacitor** is an electrical component specifically designed to store energy in an electric field. It consists of two conductive plates separated by an insulating material (dielectric). When a voltage is applied across the plates, an electric field is created, allowing the capacitor to store energy.

### Why the Other Choices are Incorrect:
- **A: Varistor**  
  - A varistor is a voltage-dependent resistor that changes its resistance with the applied voltage. It is primarily used for voltage regulation and protection against surges, not for storing energy.

- **C: Inductor**  
  - An inductor stores energy in a magnetic field when current flows through it. While it does store energy, it does so in a different manner than a capacitor, which uses an electric field.

- **D: Diode**  
  - A diode is a semiconductor device that allows current to flow in one direction only. It does not store energy; instead, it controls the flow of current in a circuit.

### Useful Formulas:
- The energy ($E$) stored in a capacitor can be calculated using the formula:
  
  $$E = \frac{1}{2} C V^2$$

  where:
  - $E$ = energy in joules
  - $C$ = capacitance in farads
  - $V$ = voltage across the capacitor in volts

This formula illustrates how the energy stored in a capacitor depends on both its capacitance and the voltage applied. Understanding this concept is crucial for the Extra Class exam.