Electrical Engineering All Engineering Career

The presence of an uncharged conductor near a charged one increases the capacity of the charged conductor.

For high frequency circuits, the capacitor preferred is usually the mica capacitor. Mica capacitors offer low loss and stability over a wide range of frequencies, making them suitable for high-frequency applications. So, the correct answer is "mica capacitor."

The capacitance of a capacitor is influenced by all of the factors you mentioned:

1. Plate area: The capacitance is directly proportional to the area of the plates. Increasing the plate area increases the capacitance.

2. Plate separation: The capacitance is inversely proportional to the separation between the plates. Decreasing the plate separation increases the capacitance.

3. Nature of dielectric: The type of dielectric material between the plates affects the capacitance. Different dielectric materials have different permittivity values, which influence the capacitance.

So, the correct answer is "all of the above."

The breakdown voltage for paper capacitors typically falls within the range of 200 to 1600 volts. So, the correct option is "200 to 1600 volts."

Electrolytic capacitors can be used for both AC (Alternating Current) and DC (Direct Current) applications. So, the correct option is "Electrolytic."

The property of a capacitor that delays any change of voltage across it is capacitance. Capacitors store energy in the form of an electric field between their plates, and this stored energy opposes any change in voltage across the capacitor, causing a delay in voltage changes. So, the correct option is "Capacitance."

Permittivity is expressed in Farad per meter (F/m). So, the correct option is "Farad/metre."

A paper capacitor, also known as a paper condenser, is typically of fixed value. It does not have polarity like electrolytic capacitors, and it is not variable. So, the correct option is "usually of fixed value."

When a third charge is placed between two equal and similar charges, it will experience a force of repulsion from each of the two charges. If the third charge is placed exactly in the middle, the forces exerted by the two charges will cancel out, resulting in stable equilibrium. So, the correct option is "remain in stable equilibrium."

The force between two charges is inversely proportional to the square of the distance between them, according to Coulomb's law. 

So, if the distance between the charges is decreased from 50 mm to 10 mm, the force will increase by \(\left(\dfrac{50}{10}\right)^2 = 25\) times.

Thus, the force between them will be 25 times larger than before. So, the correct option is "25 times larger than before."