Electrical Circuits 1-450 Flashcards
- Conventional flow assumes charges flow from ______.
a. positive to negative
b. positive to positive
c. negative to positive
d. negative to negative
Positive to Negative
- Electron flow assumes charges flow from ______.
a. negative to positive
b. negative to negative
c. positive to negative
d. positive to positive
negative to positive
- Series resonance occurs when _______.
a. XL = XC
b. XL = R
c. Z = R
d. Both A and C
Both A and C
- The symbol Q refers to ______.
a. Resonance quotient
b. Quality Factor
C. Power quotient
D. Qualification test
Quality Factor
- The ratio of W/VA in an ac circuit means _______.
a. power factor
b. reactive factor
c. quality factor
d. load factor
Power Factor
- What is the reciprocal of quality factor?
a. Power Factor
b. Reactive Factor
c. Dissipation Factor
d. 1/Q factor
Dissipation factor
- In liquids and gasses, ionization current results from a flow of _____.
a. positive or negative ions
b. free electrons
c. ions that are lighter in weight than electrons
d. protons
Free electrons
- VL = VC in a series RLC circuit when
a. the value of the impedance is minimum
b. the power factor is zero
c. the current leads the total voltage by 90 degrees
d. the total voltage is zero
the value of the impedance is minimum
- Property of an electric circuit that dissipates electric energy.
a. Reactance
b. Impedance
c. Resistance
d. Conductance
Resistance
- What is the other name of relative permittivity?
a. Dielectric strength
b. Potential gradient
c. Breakdown voltage
d. Specific inductive capacity
Specific inductive capacity
- In a series RLC circuit:
a. the current lags VL by 90 degrees
b. the current leads VL by 90 degrees
c. XL leads XC by 90 degrees
d. Z = jXL at resonance
the current lags VL by 90 degrees
- Resistor with colored bands in the body is kniwn as ______.
a. wire-wound resistor
b. carbon-composition resistor
c. potentiometer
d. rheostat
Carbon-composition resistor
- In a resonant circuit, if Q is greater than or equal to 10, resonant frequency _______ bandwidth.
a. bisects
b. exceeds
c. is less than
d. is equal to
bisects
- Which of the following conditions is not true for a series RLC circuit at resonance?
a. Z = jXL
b. XL = Xc
c. the power factor is one
d. the magnitude of Z is sqrt( (R^2) + (XL - Xc)^2 )
Z = jXL
- The current is _____ times the maximum current at half-power points of a resonance curve.
a. 0.707
b. 1.414
c. 0.5
d. 0.632
0.707
- A gang capacitor is a variable capacitor in which capacitance is varied by changing the _______.
a. dielectric
b. number of plates
c. plate area
d. distance between plates
plate area
- In an ac circuit with inductive reactance, the _________.
a. phase angle of the circuit is always 45 degrees
b. voltage across the inductancee must be 90 degrees out-of-phase with the applied voltage
c. current through the inductance lags its induced voltage by 90 degrees
d. current through the inductance and voltage across it are 180 degrees out-of-phase
current through the inductance lags its induced voltage by 90 degrees
- If three 9 mH inductors are connected in parallel without mutual inductance, then the toal inductance is _______.
a. 3 mH
b. 9 mH
c. 27 mH
d. 18 mH
3 mH
Solution:
For identical inductors in parallel,
LT (Total Inductance) = L/n
= 9 mH/3
= 3 mH
- What is the specific resistance of a pure germanium?
a. 55 ohms-cm
b. 55 ohms-m
c. 55 ohms-mm
d. 55 kiloohms-m
55 ohms.cm
- Two capacitors of capacitance 9 uF and 18 uF in series will have a total capacitance of _________.
a. 27 uF
b. 162 uF
c. 6 uF
d. 180 uF
6 uF
Solution:
CT( total capacitance) = (C1C2)/C1+C2
= (( 9uF )( 18uF ))/ ( 9uF )+(18uF)
= 6uF
- Two capacitors of capacitance 9 uF and 18 uF in series will have a total capacitance of _________.
a. 27 uF
b. 162 uF
c. 6 uF
d. 180 uF
6 uF
Solution:
CT( total capacitance) = (C1C2)/C1+C2
= (( 9uF )( 18uF ))/ ( 9uF )+(18uF)
= 6uF
- In a series RLC circuit:
a. increasing the frequency decreases the resistance
b. increasing the frequency increases the resistance
c. both XL and Xc change as frequency changes
d. impedance will always decrease
both XL and Xc change as frequency changes
- A series RLC circuit has a ________ power factor at its half-power points.
a. unity
b. leading
c. lagging
d. either B or C
- Kirchhoff’s laws (KCL and KVL) are applicable to ________.
a. dc circuits alone
b. ac circuits alone
c. dc as well as ac circuits
d. passive networks alone
