The question asks about the primary role of a dielectric material when inserted into a capacitor. We need to understand how a dielectric affects the electrical properties of a capacitor.
D) Increase capacitance — As explained, the primary role of a dielectric is to increase the capacitance of the capacitor. By having a dielectric constant (\(\epsilon_r\)) greater than 1, it increases the overall permittivity between the plates, leading to a higher capacitance.
The question asks to identify a dielectric material from the given options. A dielectric material is an electrical insulator that can be polarized by an applied electric field. It does not conduct electricity but stores electrical energy.
D) Mica is a classic example of a dielectric material. It is an excellent electrical insulator with high dielectric strength, meaning it can withstand high electric fields without breaking down. It is widely used in capacitors due to its stable electrical properties over a wide range of temperatures and frequencies.
The question asks about the primary function of an insulator. To answer this, we need to recall the definition and properties of insulators in the context of electricity.
Correct Option: C) Resist electric current
The question asks to identify which option is NOT a use of conductive materials. Conductive materials are those that allow electricity or heat to pass through them easily. We need to evaluate each option based on this property.
Correct Option: B) Thermal insulation
Thermal insulation is designed to resist the flow of heat. Therefore, materials used for thermal insulation are typically poor conductors of heat, also known as insulators, not conductive materials.
The question asks about the behavior of an insulator's resistance with increasing temperature. To answer this, we need to understand the fundamental properties of insulators and how temperature affects the availability of charge carriers within them.
A) Decreases — As the temperature of an insulator increases, more electrons gain enough thermal energy to break free and become charge carriers, leading to a decrease in its electrical resistance.
The question asks about materials typically used as insulators in high-voltage applications. We need to identify which of the given options possesses the necessary properties for effective high-voltage insulation.
Correct Option: B) Ceramics are inorganic, non-metallic materials with high dielectric strength, excellent thermal stability, and good mechanical properties, making them ideal for high-voltage insulators in applications like power transmission lines and electrical equipment.