Capacitors MCQs
Practice and Learn through MCQs and Quizzes. W3Definitions.com have 49 Capacitors MCQs
A capacitor and an output resistor form a series circuit with a square wave applied. The circuit is:
- A. an integrator
- B. a differentiator
- C. a multiplier
- D. a divider
- Correct Answer: Option B
A capacitor is constructed of two parallel:
- A. conductors
- B. semiconductors
- C. inductors
- D. dielectrics
- Correct Answer: Option A
A capacitor stores energy within a dielectric between the conducting plates in the form of:
- A. a magnetic field
- B. positive voltage
- C. negative voltage
- D. an electric field
- Correct Answer: Option D
A capacitor’s rate of charge is considered:
- A. magnetic
- B. a current block
- C. linear
- D. exponential
- Correct Answer: Option D
A circuit whose output voltage is proportional to the rate of change of the input voltage is called a(n) ______ .
- A. differentiator
- B. integrator
- C. curve averager
- D. mixer
- Correct Answer: Option A
A discharged capacitor has ______ charges on its plates.
- A. no
- B. unequal
- C. equal
- D. negative
- Correct Answer: Option C
A resistor and an output capacitor form a series circuit with a square wave applied. The circuit is:
- A. an integrator
- B. a differentiator
- C. a multiplier
- D. a divider
- Correct Answer: Option A
A source voltage across a capacitor will:
- A. lead the current by 90 degrees
- B. lead the current by 180 degrees
- C. lag the current by 90 degrees
- D. lag the current by 180 degrees
- Correct Answer: Option C
After a capacitor has charged for 1 tc, what percentage of current remains in the resistor?
- A. 63.2
- B. 36.8
- C. 13.5
- D. 5.0
- Correct Answer: Option B
After which time constant can a capacitor be considered to be fully charged?
- A. first
- B. third
- C. fifth
- D. seventh
- Correct Answer: Option C
An 8 V power source is charging a capacitor. How many volts will be across the capacitor at the second time constant?
- A. 1 volt
- B. 3 volts
- C. 5 volts
- D. 7 volts
- Correct Answer: Option D
As a capacitor is being charged, current flowing into the capacitor will:
- A. increase
- B. decrease
- C. remain the same
- D. cannot tell
- Correct Answer: Option B
As a capacitor is being charged, the voltage across its terminals will:
- A. increase
- B. decrease
- C. remain the same
- D. oppose the source
- Correct Answer: Option A
Capacitor value markings are usually:
- A. alphanumeric
- B. color dabs
- C. standard
- D. white print
- Correct Answer: Option A
For a given charge difference, electrostatic field strength varies according to:
- A. plate differential
- B. plate area
- C. plate distance
- D. dielectric quantity
- Correct Answer: Option B
How is ac current related to ac voltage in a purely capacitive circuit?
- A. AC current is 0.707 of the ac voltage.
- B. AC current lags ac voltage.
- C. AC current is 0.637 of the ac voltage.
- D. AC current leads ac voltage.
- Correct Answer: Option D
If a capacitor is placed across a 20 V source, what will be the amount of charge after 5 tc?
- A. 5.0 V
- B. 12.8 V
- C. 13.5 V
- D. 20 V
- Correct Answer: Option D
If a charged capacitor is disconnected from a circuit, it will:
- A. immediately discharge
- B. recharge
- C. remain charged
- D. leak the charge
- Correct Answer: Option D
If a current of 40 mA flows through a series circuit consisting of a 0.4 F capacitor and a resistor in series with a 4 kHz, 40 Vac source, what is the total circuit impedance?
- A. 10
- B. 100
- C. 1 k
- D. 1 M
- Correct Answer: Option C
If an open capacitor is checked with an ohmmeter, the needle will:
- A. stay on zero
- B. stay on infinity
- C. move from zero to infinity
- D. move from infinity to zero
- Correct Answer: Option B
If C1, a 4.7 F capacitor, and C2, a 3.3 F capacitor are in series with 18 Vdc applied, what is the voltage across C1?
- A. 3.3 V
- B. 7.4 V
- C. 6.6 V
- D. 9.4 V
- Correct Answer: Option B
If the dielectric constant of a capacitor is decreased, then its capacitance will:
- A. increase
- B. decrease
- C. remain the same
- D. be destroyed
- Correct Answer: Option B
If the reactive power of a circuit is 50 mW while the apparent power is 64 mW, then what is the true power of the circuit?
- A. 14 mW
- B. 36 mW
- C. 40 mW
- D. 114 mW
- Correct Answer: Option C
In a 20 Vac series RC circuit, if 20 V is measured across the resistor and 40 V is measured across the capacitor, the applied voltage is:
- A. 45 V
- B. 50 V
- C. 55 V
- D. 60 V
- Correct Answer: Option A
In an ac circuit, a capacitor and an output resistor are connected in series with an ac signal. What filter action will be the result?
- A. bandpass
- B. low-pass
- C. high-pass
- D. band-stop
- Correct Answer: Option C
In an ac circuit, an output capacitor and a resistor are connected in series with an ac signal. What filter action will be the result?
- A. bandpass
- B. low-pass
- C. high-pass
- D. band-stop
- Correct Answer: Option B
Most older types of paper capacitors have been replaced by which type of construction?
- A. electrolytic
- B. plastic film
- C. oxide casing
- D. waxed paper
- Correct Answer: Option B
Power stored from the source and then returned to the source is called:
- A. apparent power
- B. impedance power
- C. reactive power
- D. true power
- Correct Answer: Option C
The material used between the plates of a capacitor is called its:
- A. insulation material
- B. dielectric material
- C. separation material
- D. plate-divider material
- Correct Answer: Option B
The strength of an electric field at a given point is proportional to the potential difference on the plates and inversely proportional to the:
- A. plate separation
- B. negative plate only
- C. field strength
- D. charge difference
- Correct Answer: Option A
The term ______ is derived from a mathematical function in calculus.
- A. differentiator
- B. integrator
- C. filter
- D. voltage-divider
- Correct Answer: Option B
What do variable capacitors use for dielectric?
- A. ceramic, electrolytic, mica, or paper
- B. air, ceramic, mica, or plastic
- C. ceramic, paper, plastic, or mica
- D. mica, ceramic, plastic, or electrolytic
- Correct Answer: Option B
What is the angle theta value for a 5.6 F capacitor and a 50-ohm resistor in series with a 1.1 kHz, 5 Vac source?
- A. 27.3 degrees
- B. 62.7 degrees
- C. –27.3 degrees
- D. –62.7 degrees
- Correct Answer: Option C
What is the capacitive reactance if I = 1 amp, V = 2 volts, C = 5 F, and frequency = 10 Hz?
- A. 0.2
- B. 0.5
- C. 0.02
- D. 0.003
- Correct Answer: Option D
What is the dielectric constant for ceramic?
- A. between 6 and 8000
- B. 5.0
- C. between 5 and 1000
- D. 3000
- Correct Answer: Option A
What is the impedance of a series RC circuit that consists of a 0.22 F capacitor and a 200-ohm resistor connected to a 3 kHz source?
- A. 214 ohms
- B. 313 ohms
- C. 414 ohms
- D. 880 ohms
- Correct Answer: Option B
What is the impedance of an ac RC parallel circuit if the resistance is 12 ohms and the capacitive reactance equals 5 ohms?
- A. 0.2 ohms
- B. 3.5 ohms
- C. 4.6 ohms
- D. 13 ohms
- Correct Answer: Option C
What is the power factor if the apparent power of a circuit is 5 W, while the true power is 4 W?
- A. 0.0 W
- B. 0.8 W
- C. 1.0 W
- D. 1.25 W
- Correct Answer: Option B
What is the reactance value for a capacitor installed in a dc circuit?
- A. zero
- B. moderate
- C. infinite
- D. cannot tell
- Correct Answer: Option C
What is the total current for a 5 MHz, 1 Vac circuit that consists of a 27 pF capacitor and a 1 k resistor connected in parallel?
- A. 459 A
- B. 647 A
- C. 1.31 mA
- D. 1.85 mA
- Correct Answer: Option C