AC quiz

(Refer to Figure 5.) What is the impedance of an ac-series circuit consisting of an inductor with a reactance of 10 ohms, a capacitor with a reactance of 4 ohms, and a resistor with a resistance of 8 ohms?

• 10 ohms.

• 22 ohms.

• no text provided.

• 5.29 ohms

The term that describes the combined resistive forces in an AC circuit is

• impedance (Z).

• total resistance (RT).

• resistance (R).

• no answer text provided.

In an ac circuit, the effective voltage is

• equal to the maximum instantaneous voltage.

• greater than the maximum instantaneous voltage.

• less than the maximum instantaneous voltage.

• No answer text provided.

An instrument that displays AC waveforms graphically is a/an

• ammeter

• wavemeter

• oscilloscope

• No answer text provided.

What is the phase relationship between the current and voltage in a purely capacitive circuit?

• the current leads the voltage by 90 degrees

• the current lags the voltage by 90 degrees

• the current leads the voltage by 0 degrees

• no answer text provided.

What is the total inductance of the circuit shown in Figure 2?

Figure 2

• 15 mH

• 2 mH

• 14.3 mH

• no answer text provided.

Transfer of electric energy from one circuit to another without the aid of electrical connections

• is called induction

• can cause excessive arcing and heat, and as a result is practical for use only with low voltages/amperages

• No answer text provided.

• is called capacitance

The power ratio of a transformer is usually less than 1:1 due to:

• using a turns ratio other than 1:1.

• hysteresis loss and eddy currents.

• using a step-down turn ratio.

• No answer text provided

If a circuit contains 10 ohms of resistance, 20 ohms of inductive reactance, and 30 ohms of capacitance, it is said to be

• inductive

• in resonance

• capacitive

• no answer text provided.

If a capacitor, rated at 80 pF, is connected in series with a 120 K ohm resistor and connected to a 100 volts DC source, how long will it take for the capacitor to charge to 63.2 volts? (1 time constant)

• 12 seconds

• 8 seconds

• 9.6 µseconds

• no answer text provided.