Q4/ A parallel plate capacitor consists of two metal plates, each of area S=150 cm², separated by a vacuum gap d=0.60 cm thick. 1. What is the capacitance of this device? (25 marks) 2. What potential difference must be applied between the plates if the capacitor is to hold a charge of magnitude Q=1.00x 10 μC on each plate? (The value of & = 8.85 x 10-12 Nm² C²) work expended in carrying 2C from B(1.9.1)

In a pure capacitive circuit, does the current lead or lag the voltage?

Three capacitors having capacitance values of 20F,40F, and 50F are connected in parallel to a 60 - Hz power line. An ammeter indicates a circuit current of 8.6 amperes. How much current is flowing through the 40F capacitor?

A 15-F AC capacitor is connected in series with a 50 resistor. The capacitor has a voltage rating of 600 WVDC. The capacitor and resistor are connected to a 480-V, 60-Hz circuit. Is the voltage rating of the capacitor sufficient for this connection?

You are working in an industrial plant. You have been instructed to double the capacitance connected to a machine. The markings on the capacitor, however, are not visible. The capacitor is connected to 560 volts and an ammeter indicates a current of 6 amperes flowing to the capacitor. What size capacitor should be connected in parallel with the existing capacitor? What is the minimum AC voltage rating of the new capacitor? What is the minimum DC voltage rating of the new capacitor? What is the minimum KVAR size that can be used in this installation?

A pure capacitive circuit is connected to a 480-volt, 60-Hz power source. An ammeter indicates a current flow of 24 amperes. The circuit current must be reduced to 16 amperes by connecting a second capacitor in series with the first. What is the value of the existing capacitor? What value capacitor should be connected in series with the original capacitor to limit the circuit current to 16 amperes?

An inductor has a current flow of 3 amperes when connected to a 240-volt, 60-Hz power line. The inductor has a wire resistance of 15 . What is the Q of the inductor?

You find that a 25-F capacitor connected to 480 VAC is defective. The storeroom has no capacitors with a 480-VAC rating. However, you find two capacitors rated at 50 F and 370 VAC. Can these two capacitors be connected in such a manner that they can replace the defective capacitor? If yes, explain how they are connected and why the capacitors will not be damaged by the lower voltage rating. If no, explain why they cannot be used without damaging the capacitor.

In reference to the load, how are capacitors connected to help prevent voltage spikes and surges? Are capacitors connected in parallel or in series with the load?

How many valence electrons are generally contained in materials used for insulators?