Alberta Boilers Safety Association (ABSA) Practice Test

When working with capacitors, what is the effect of increasing the dielectric material thickness?

1. Increased capacitance

2. Decreased capacitance

3. No effect on capacitance

4. Capacitance becomes zero

The correct answer is: Decreased capacitance

When the thickness of the dielectric material between the plates of a capacitor is increased, the capacitance of the capacitor decreases. This can be understood by analyzing the fundamental relationship that defines capacitance, which is given by the formula: \[ C = \frac{\varepsilon A}{d} \] where \( C \) is the capacitance, \( \varepsilon \) is the permittivity of the dielectric material, \( A \) is the area of the plates, and \( d \) is the distance between the plates (the thickness of the dielectric). As the thickness \( d \) increases, the distance between the plates also increases. Since capacitance is inversely proportional to the distance between the plates, increasing the thickness of the dielectric results in decreased capacitance. In practical terms, this means that the capacitor will store less charge at a given voltage when the dielectric thickness is increased. This principle is essential in designing and understanding capacitors in various electrical and electronic applications.