Inductors MCQs
Practice and Learn through MCQs and Quizzes. W3Definitions.com have 69 Inductors MCQs
A change of one ampere per second in an inductor that induces a voltage of one volt is considered as which unit value?
- A. a lenz
- B. an ohm
- C. a farad
- D. a henry
- Correct Answer: Option D
A loaded transformer will achieve mutual induction when:
- A. secondary current increase causes a primary current decrease
- B. primary current is increased by an increase in secondary current
- C. primary current is decreased by an increase in secondary current
- D. secondary current decrease causes a primary current increase
- Correct Answer: Option B
A magnetic circuit breaker will open to protect equipment only when:
- A. voltage is exceeded
- B. an open is in the equipment
- C. the equipment is operating properly
- D. current is exceeded
- Correct Answer: Option D
A magnetic field has:
- A. polar fields
- B. lines of force
- C. magnetomotive force
- D. lines of reluctance
- Correct Answer: Option B
A series RL filter circuit with an output across the inductor will result in what type of filtering?
- A. passing of the higher frequencies
- B. passing of the lower frequencies
- C. blocking of the higher frequencies
- D. blocking of a certain range of frequencies
- Correct Answer: Option A
A transformer is used:
- A. to couple electric energy from one dc circuit to another
- B. to couple electric energy from an ac circuit to a dc circuit
- C. to couple electric energy from a dc circuit to an ac circuit
- D. to couple electric energy from one ac circuit to another
- Correct Answer: Option D
A transformer will have:
- A. primary and secondary windings
- B. primary and secondary current
- C. primary wattage producing secondary current
- D. different frequencies for the primary and secondary
- Correct Answer: Option A
A turns ratio of 5 for a transformer implies:
- A. more primary turns than secondary turns
- B. more secondary current than primary current
- C. larger source impedance than load impedance
- D. more secondary turns than primary turns
- Correct Answer: Option D
A utility pole transformer used to supply a residential customer with two phases uses:
- A. two phases on the primary
- B. a center tap on the secondary
- C. a separate ground for each phase
- D. a small coefficient of coupling
- Correct Answer: Option B
A value of “ten to the eighth power magnetic lines of force” is for the term:
- A. field
- B. flux
- C. coulomb
- D. weber
- Correct Answer: Option D
A voltage is induced in a transformer secondary winding by the action of the:
- A. secondary magnetic field
- B. primary turns ratio
- C. primary magnetic field
- D. secondary counter emf
- Correct Answer: Option C
An RL integrator can act as a __________ filter and an RC differentiator can act as a __________ filter.
- A. high-pass, high-pass
- B. low-pass, low-pass
- C. high-pass, low pass
- D. low-pass, high-pass
- Correct Answer: Option D
As a generator armature passes the 270 degree point, the induced voltage is:
- A. at maximum negative
- B. between maximum negative and zero
- C. at maximum positive
- D. between zero and maximum positive
- Correct Answer: Option A
As current travels within a conductor:
- A. the magnetic field aids the current
- B. a magnetic field is developed around it
- C. the wire tries to point north
- D. an electrostatic field opposes the current
- Correct Answer: Option B
Counter emf or induced voltage is:
- A. inversely proportional to the change in current
- B. directly proportional to the change in time
- C. directly proportional to the inductance in henrys
- D. inversely proportional to the inductance in henrys
- Correct Answer: Option C
Current will cause a magnetic field in a conductor as follows:
- A. An ac current causes a fixed polarity magnetic field.
- B. A dc current causes a fixed polarity magnetic field.
- C. A dc current causes an alternating magnetic field.
- D. An ac current causes a fixed polarity magnetic field and a dc current causes an alternating magnetic field.
- Correct Answer: Option B
During a current change, the ability of a conductor to produce counter emf within itself is called:
- A. back emf
- B. self-induction
- C. a henry
- D. impedance
- Correct Answer: Option B
Electricity may be generated by a wire:
- A. carrying current
- B. wrapped as a coil
- C. that has neutral domains
- D. passing through a flux field
- Correct Answer: Option D
Electromagnetic induction is the generation of:
- A. electricity from magnetism
- B. electricity from electricity
- C. magnetism from electricity
- D. magnetism from magnetism
- Correct Answer: Option A
Electromagnetism is the:
- A. magnetic field caused by a permanent magnet
- B. action between a permanent and an artificial magnet
- C. magnetic field action with a current-carrying wire
- D. current in the coil
- Correct Answer: Option C
Faraday’s law states that the:
- A. direction of the induced voltage produces an opposition
- B. direction of an induced current produces an aiding effect
- C. emf depends on the rate of cutting flux
- D. emf is related to the direction of the current
- Correct Answer: Option C
Fixed transformers have:
- A. a center-tapped secondary
- B. multiple windings
- C. turns ratios that cannot be changed
- D. a multiple-tapped secondary
- Correct Answer: Option C
If 360 Vac is the output of a 300-turn secondary winding, what is the input voltage when the primary winding has 150 turns?
- A. 2.4 Vac
- B. 150 Vac
- C. 180 Vac
- D. 720 Vac
- Correct Answer: Option C
If the primary of a 4:1 turns transformer dissipates 5 W, what is the secondary power?
- A. 5.0 W
- B. 1.25 pW
- C. 9.5 W
- D. 20.0 mW
- Correct Answer: Option A
If you wanted to decrease the inductance of a coil, you might increase the:
- A. number of turns
- B. permeability of the core
- C. spacing between turns
- D. area of the coil
- Correct Answer: Option C
In a transformer, what will happen to the primary current if the secondary magnetic field increases?
- A. Ip will increase.
- B. Ip will be canceled.
- C. Ip will remain the same.
- D. Ip will decrease.
- Correct Answer: Option A
Indication of transformer primary and secondary voltage relationships is accomplished by:
- A. color-coded wires
- B. dot notation
- C. black, rather than gray, casings
- D. winding ratios
- Correct Answer: Option B
Inductance is:
- A. directly proportional to the length of the coil
- B. directly proportional to the number of turns on the coil
- C. inversely proportional to the cross-sectional area of the coil
- D. inversely proportional to the permeability
- Correct Answer: Option B
On a schematic, dashed lines between two vertical coils usually mean the transformer has:
- A. an air core
- B. an iron core
- C. a nonmetallic core
- D. a ferrite core
- Correct Answer: Option D
Opposition to current flow without the dissipation of energy is called:
- A. resistance
- B. inductive reactance
- C. counter emf
- D. impedance
- Correct Answer: Option B
Reactance in an inductive circuit will:
- A. increase with frequency
- B. decrease with frequency
- C. be independent from frequency
- D. depend on the value of XC
- Correct Answer: Option A
The electrical energy consumed by a coil is stored in the form of:
- A. an electrical field
- B. a force field
- C. an electrostatic field
- D. a magnetic field
- Correct Answer: Option D
The four factors determining inductance are the number of turns, coil length, coil area, and:
- A. permeability
- B. reluctance
- C. counter emf
- D. coefficient of coupling
- Correct Answer: Option A
The output phase for a transformer is:
- A. in phase with the input
- B. out of phase with the input
- C. dependent on the direction of the primary and secondary windings
- D. dependent on the frequency of the primary source
- Correct Answer: Option C
The polarity of induced voltage while a field is collapsing is:
- A. independent of the force creating it
- B. opposite to the force creating it
- C. identical to the force creating the field
- D. present only if the force is stationary
- Correct Answer: Option B
The time difference, or lag, between flux density and magnetizing force is known as:
- A. eddy current
- B. magnetic saturation
- C. hysteresis
- D. coercivity
- Correct Answer: Option C
The time required for one weber of flux to cut a conductor and produce one volt is:
- A. one revolution
- B. one second
- C. one millisecond
- D. four revolutions
- Correct Answer: Option B
The unit of flux density is:
- A. magnetomotive force
- B. a weber
- C. a maxwell
- D. a tesla
- Correct Answer: Option D
What does Faraday’s law concern?
- A. a magnetic field in a coil
- B. a magnetic field cutting a conductor
- C. a magnetic field hystersis
- D. a magnetic field in a conductor
- Correct Answer: Option B
What happens when moving expanding lines of force encounter a conductor?
- A. Current increases.
- B. Voltage is induced.
- C. Resistance is reduced.
- D. Power is increased.
- Correct Answer: Option B