The correct answer is: D. Conductors separated by an insulator
A capacitor is an electrical device that stores energy in an electric field. It consists of two conductors separated by an insulator. The conductors are usually plates of metal, and the insulator is a material that does not conduct electricity, such as air or paper. When a voltage is applied to the capacitor, an electric field is created between the plates. This field stores energy, which can be released when the voltage is removed.
Option A is incorrect because a capacitor does not have a ceramic plate and a mica disc. A ceramic plate is a type of insulator, and a mica disc is a type of dielectric. A dielectric is a material that can be polarized by an electric field. When a dielectric is placed between two conductors, it increases the capacitance of the capacitor.
Option B is incorrect because a capacitor does not have insulators separated by a dielectric. A capacitor has two conductors separated by an insulator. The insulator prevents the flow of current between the conductors, but it allows the electric field to exist between them.
Option C is incorrect because a capacitor does not have silver-coated insulators. A silver-coated insulator is a type of capacitor, but it is not the only type of capacitor. Other types of capacitors include ceramic capacitors, mica capacitors, and paper capacitors.
In conclusion, the correct answer is: D. Conductors separated by an insulator