Review Questions alternating current

An electric current always produces __________.

a. mutual inductance

b. a magnetic field

c. capacitive reactance

d. high voltage

b. a magnetic field

The number of cycles an alternating electric current undergoes per second is known as _________.

a. amperage

b. frequency

c. voltage

d. resistance

b. frequency

Which of the following conditions exist in a circuit of pure resistance?

a. The voltage and current are in phase

b. The voltage and current are 90 degrees out of phase.

c. The voltage and current are 120 degrees out of phase.

d. The voltage and current are 180 degrees out of phase.

a. The voltage and current are in phase

What is the peak voltage in a circuit with an RMS voltage of 120V AC?

a. 117 volts

b. 120 volts

c. 150 volts

d. 170 volts

d. 170 volts

120*1.414 (rms) = 169.71 volts

In a purely resistive AC circuit where 240V is applied across a 10-ohm resistor, the amperage is ______.

a. 10A

b. 24A

c. 60A

d. 120A

b. 24A

When the current increases in an AC circuit, what role does inductance play?

a. It increases the current.

b. It plays no role at all.

c. It causes the overcurrent protection to open.

d. It reduces the current.

d. it reduces the current

All of the following factors increase the inductance of a coil, except a ________.

a. greater number of turns

b. longer core

c. wider coil

d. magnetic core

b. longer core

Which of the following conditions exist in a circuit of pure inductance?

a. The voltage and current are in phase.

b. The voltage and current are 90 degrees out of phase.

c. The voltage and current are 120 degrees out of phase

d. The voltage and current are 180 degrees out of phase.

b. The voltage and current are 90 degrees out of phase

True of False? Reactance increases with an increase in inductance.

a.True

b.False

a. TRUE

Capacitance is measure in _______.

a. farads

b. joules

c. henrys

d. amps

a. farads

The total capacitance of two 15uF capacitors connected in parallel is _______.

a. 5uF

b. 10uF

c. 15uF

d. 30uF

d. 30uf

The opposition to current flow offered by the capacitance of a circuit is known as ______.

a. mutual inductance

b. pure resistance

c. inductive reactance

d. capacitative reactance

d. capacitative reactance

The total opposition to current flow in an AC circuit is known as __________.

a. resistance

b. capacitive reactance

c. inductive reactance

d. impedance

Impedance

A power factor is not an angular measure, but a numerical ratio with a value between 0 and 1, equal to the _______.

a. sine of the phase angle

b.tangent of the phase angle

c. cosine of the phase angle

d. cotangent of the phase angle

c. cosine of the phase angle

The two windings of a conventional transformer are known as the ________.

a. mutual and inductive windings

b. high and low voltage windings

c. primary and secondary windings

d. step-up and step-down windings

c. primary and secondary windings