Title: L/C Test
Course: Electrical Theory (IC 101-IC 101) > Section: Assessments

Q: A capacitor appears as an open to a constant DC source.
- True
- False
A: True

Q: A series circuit contains 30 ohms of resistance and 40 ohms of inductive reactance.  What is the impedance of the circuit?
- 50 ohms
- 30 ohms
- 2k ohms
- 100 ohms
- 20 ohms
A: 50 ohms

Q: An inductance has reactance of 2.89k ohms to a frequency of 100Hz.  What is its reactance to a frequency of 750 Hz?
- 50 ohms
- 3.2K ohms
- 21.67k ohms
- 33.75k ohms
- there is not enough information given to find the correct answer.
A: 50 ohms

Q: Capacitors are employed to
- store energy.
- block direct current.
- pass alternating current.
A: store energy.

Q: If the DC resistance of an inductor is infinity, it is likely that the coil is open.
- True
- False
A: True

Q: If the frequency of the voltage applied to a series LR circuit is increased:
- the impedance of the circuit decreases.
- the reactance of the circuit increases.
- both impedance and reactance decreases.
- the phase angle decreases.
- both answers A and D are correct.
A: the impedance of the circuit decreases.

Q: In a capacitive circuit if the capacitance is doubled the reactance is
- half
- doubled
- remains the same
A: half

Q: In a series AC circuit with 90 ohms Xc and 90 ohms resistance, the phase angle equals
- -90 degrees
- -45 degrees
- 0 degrees
- 90 degrees
A: -90 degrees

Q: In an AC circuit the voltage drop across the capacitor is 18 volts and the voltage drop across the resistor is 25 volts.  The applied voltage is:
- 43 volts
- 7 volts
- 21.5 volts
- 30.8 volts
A: 43 volts

Q: In an inductive circuit, the voltage _________ the current by 90 degrees.
- lags
- is zero
- leads
A: lags

Q: The capacitive reactace of a circuit is 132.5 ohms.  If the capacitor has a value of 8 ufd, what is the frequency of the applied voltage?
- 60 Hz
- 120 Hz
- 150 Hz
A: 60 Hz

Q: The capacitive reactance of a capacitor increases as the frequency
- increases.
- decreases.
- changes.
- gets wider.
A: increases.

Q: The current in a capacitive circuit
- Is in phase with the voltage
- Is 180 degrees out of phase with the voltage
- Leads the voltage by 90 degrees
- Lags the voltage by 90 degrees
A: Is in phase with the voltage

Q: The formula for inductive reactance is 2πfL. (π =pi)
- True
- False
A: True

Q: The type of capacitor that requires polarity consideration when connected in a circuit is
- electrolytic
- mica
- paper
- ceramic
A: electrolytic

Q: The voltage and turns ratio of a transformer are inversely proportional.
- True
- False
A: False

Q: The voltage rating of a capacitor is increased by
- Increasing the plate seperation
- decreasing the plate seperation
- increasing the plate area
- answers b and c
A: Increasing the plate seperation

Q: Two capacitors in series have a total capacitance of 2 ufd.  If the capacitance of one is 3 ufd, what is the capacitance of the other?
- 1 ufd
- 1.2 ufd
- 5 ufd
- 6 ufd
A: 1 ufd

Q: What is the reactance of a 100mH inductor at a frequency of 10k Hz?
- 6.28 ohms
- 200 ohms
- 628 ohms
- 2000 ohms
- 6280 ohms
A: 6.28 ohms

Q: When the voltage across a capacitor is doubled, the stored charge
- stays the same
- is halved
- increased by four
- doubles
A: stays the same

Q: When two capacitors are in parallel with a voltage source, the smaller capacitor will have the larger voltage.
- True
- False
A: False

Q: Current
A: 5 mA

Q: Phase angle in degrees
A: 53.13

Q: Resistance in ohms
A: 6000

Q: Voltage across the inductor
A: 40V

Q: Voltage across the resistor
A: 30V

Q: Impedance
A: 894

Q: Line current
A: 111.803 mA

Q: Phase angle
A: -26.565 degrees

Q: Capacitive current
A: 120mA

Q: Impedance
A: 707 ohms

Q: Phase Angle
A: 45 degrees

Q: Resistive current
A: 120mA

Q: Total current
A: 169.705mA

Q: Capacitive reactance
A: 1592 ohms

Q: Current
A: 50mA

Q: Impedance
A: 1994 ohms

Q: Voltage across capacitor
A: 80V

Q: Voltage across resistor
A: 60V