Question 1

The phase angle of a parallel R-L circuit is the angle whose cosine is the ratio of

Accepted Answer

A)   resistance to impedance.
B)   impedance to resistance.
C)   resistance to reactance.
D)   reactance to resistance. B

Question 2

The admittance of a parallel a.c. circuit is the __________ its conductance and susceptance.

Accepted Answer

A)   difference between
B)   algebraic sum of
C)   vector sum of
D)   vector difference between C

Question 3

The reference phasor for a parallel a.c. circuit is the __________ phasor.

Accepted Answer

A)   supply voltage
B)   current A

Question 4

The reciprocal of impedance is called

Accepted Answer

A)   admittance.
B)   susceptance.
C)   conductance.
D)   conductivity.

Question 5

The reference phasor for any a.c. circuit is normally drawn along the

Accepted Answer

A)   positive horizontal axis.
B)   positive vertical axis.
C)   positive vertical axis
D)   negative vertical axis.

Question 6

The power factor of a parallel a.c. circuit is the ratio of

Accepted Answer

A)   resistance to impedance.
B)   conductance to admittance.
C)   true power to apparent power.
D)   each of the above.

Question 7

The reciprocal of resistance is called

Accepted Answer

A)   admittance.
B)   susceptance.
C)   conductance.
D)   conductivity.

Question 8

If a purely-resistive branch of a parallel circuit draws a current of 5 A when supplied with a voltage of 100 V, then its _________ must be __________.

Accepted Answer

A)   admittance, 20 mho
B)   susceptance, 0.05 ohm.
C)   conductance, 0.05 siemens
D)   conductivity, 20 siemens.

Question 9

Dividing an a.c. parallel circuit's phasor diagram by the reference phasor will result in

Accepted Answer

A)   an impedance diagram.
B)   an admittance diagram.
C)   a power diagram.

Question 10

Phasors are said to 'rotate'

Accepted Answer

A)   in a clockwise direction.
B)   in a counter-clockwise direction.

Question 11

The phase angle of a parallel a.c. circuit is the angle by which the ________ __________ the __________.

Accepted Answer

A)   supply voltage, leads or lags, load current
B)   load current, leads or lags, supply voltage.

Question 12

Multiplying an a.c. parallel circuit's phasor diagram by its reference phasor will result in

Accepted Answer

A)   an impedance diagram.
B)   an admittance diagram.
C)   a power diagram.

Question 13

The phase angle of a parallel R-L circuit is also equal to the angle whose cosine is the ratio of

Accepted Answer

A)   conductance to admittance.
B)   admittance to conductance.
C)   conductance to susceptance.
D)   susceptance to conductance.

Question 14

The SI unit of measurement for each of the above quantities is the

Accepted Answer

A)   ohm.
B)   mho.
C)   siemens.

Exam 20: Parallel Alternating-Current Circuits