E5F Circuit Q; reactive power; power
factor
E5F01
(A)
What is
the Q of a parallel R-L-C circuit if the resonant frequency is 14.128 MHz, L is
2.7 microhenrys and R is 18 kilohms?
A. 75.1
B. 7.51
C. 71.5
D. 0.013
E5F02
(C)
What is
the Q of a parallel R-L-C circuit if the resonant frequency is 4.468 MHz, L is
47 microhenrys and R is 180 ohms?
A. 0.00735
B. 7.35
C. 0.136
D. 13.3
E5F03
(D)
What is
the Q of a parallel R-L-C circuit if the resonant frequency is 7.125 MHz, L is
8.2 microhenrys and R is 1 kilohm?
A. 36.8
B. 0.273
C. 0.368
D. 2.73
E5F04
(B)
What is
the Q of a parallel R-L-C circuit if the resonant frequency is 7.125 MHz, L is
12.6 microhenrys and R is 22 kilohms?
A. 22.1
B. 39
C. 25.6
D. 0.0256
E5F05
(D)
What is
the Q of a parallel R-L-C circuit if the resonant frequency is 3.625 MHz, L is
42 microhenrys and R is 220 ohms?
A. 23
B. 0.00435
C. 4.35
D. 0.23
E5F06
(C)
Why is
a resistor often included in a parallel resonant circuit?
A. To increase the Q and decrease the skin
effect
B. To decrease the Q and increase the resonant
frequency
C. To decrease the Q and
increase the bandwidth
D. To increase the Q and decrease the bandwidth
E5F07
(D)
What is
the term for an out-of-phase, nonproductive power associated with inductors and
capacitors?
A. Effective power
B. True power
C. Peak envelope power
D. Reactive power
E5F08
(B)
In a
circuit that has both inductors and capacitors, what happens to reactive power?
A. It is dissipated as heat in the circuit
B. It goes back and forth
between magnetic and electric fields, but is not dissipated
C. It is dissipated as kinetic energy in the
circuit
D. It is dissipated in the formation of
inductive and capacitive fields
E5F09
(A)
In a
circuit where the AC voltage and current are out of phase, how can the true
power be determined?
A. By multiplying the
apparent power times the power factor
B. By subtracting the apparent power from the
power factor
C. By dividing the apparent power by the power
factor
D. By multiplying the RMS voltage times the RMS
current
E5F10
(C)
What is
the power factor of an R-L circuit having a 60 degree phase angle between the
voltage and the current?
A. 1.414
B. 0.866
C. 0.5
D. 1.73
E5F11
(B)
How
many watts are consumed in a circuit having a power factor of 0.2 if the input
is 100-V AC at 4 amperes?
A. 400 watts
B. 80 watts
C. 2000 watts
D. 50 watts
E5F12
(A)
Why
would the power used in a circuit be less than the product of the magnitudes of
the AC voltage and current?
A. Because there is a phase
angle greater than zero between the current and voltage
B. Because there are only resistances in the
circuit
C. Because there are no reactances in the
circuit
D. Because there is a phase angle equal to zero
between the current and voltage