In the relation C = κ C0, what does C0 denote?

In the relation C = κ C0, what does C0 denote?

• A. The capacitance with a dielectric inserted
• B. The resistance of the circuit
• C. The capacitance in vacuum
• D. The inductance of the circuit

Answer: (C)

The main idea here is how a dielectric affects capacitance. The relation C = κ C0 shows that inserting a dielectric multiplies the vacuum capacitance by the dielectric constant κ. C0 is the capacitance when there is no dielectric, i.e., the capacitance in vacuum (the medium with relative permittivity εr = 1). For a parallel-plate capacitor, C0 = ε0 A / d. If a dielectric with relative permittivity κ fills the space between the plates, the permittivity becomes ε = κ ε0, and the capacitance becomes C = ε A / d = κ ε0 A / d = κ C0. So C0 denotes the capacitance in vacuum.

The main idea here is how a dielectric affects capacitance. The relation C = κ C0 shows that inserting a dielectric multiplies the vacuum capacitance by the dielectric constant κ. C0 is the capacitance when there is no dielectric, i.e., the capacitance in vacuum (the medium with relative permittivity εr = 1).

For a parallel-plate capacitor, C0 = ε0 A / d. If a dielectric with relative permittivity κ fills the space between the plates, the permittivity becomes ε = κ ε0, and the capacitance becomes C = ε A / d = κ ε0 A / d = κ C0. So C0 denotes the capacitance in vacuum.