A magnetic circuit primarily consists of magnetic flux, which is the flow of magnetic field lines through a material. Magnetic circuits are designed to control and direct this flux through specific paths.
What does inductance measure in a circuit?
A Ability to store energy
B Resistance
C Voltage
D Magnetic field strength
Inductance is the property of a circuit element (typically a coil) that opposes changes in current. It measures the ability to store energy in the form of a magnetic field when current flows through it.
How does increasing the number of turns in a coil affect inductance?
A Decreases inductance
B Increases inductance
C No effect
D Changes resistance
Increasing the number of turns in a coil increases the inductance because it strengthens the magnetic field for a given current, allowing more energy to be stored in the magnetic field.
What happens when a changing magnetic field induces a current in a conductor?
A Magnetic flux linkage
B Increased resistance
C Decreased flux
D Induced voltage
A changing magnetic field induces a voltage across a conductor due to Faraday’s Law of Induction. This induced voltage can cause a current to flow if the circuit is closed.
What is flux linkage in the context of inductance?
A Magnetic field strength
B Magnetic field lines
C The total flux through a coil
D Magnetic permeability
Flux linkage refers to the total magnetic flux passing through a coil and linked to the coil’s windings. It is a key factor in determining the inductance of the coil and the voltage induced.
How is inductance related to the rate of change of current in a circuit?
A Directly proportional
B Inversely proportional
C Unrelated
D Exponentially proportional
Inductance opposes changes in current. The voltage induced across an inductor is proportional to the rate of change of current. A faster change in current results in a higher induced voltage.
What happens when a magnetic flux is cut by a conductor?
A Electromagnetic interference
B Increased energy storage
C Induced EMF
D Decreased resistance
When a conductor cuts through a magnetic flux (due to movement or a changing magnetic field), an electromotive force (EMF) is induced in the conductor. This is the principle behind generators and transformers.
Which material is commonly used for increasing the inductance of a coil?
A Copper
B Iron
C Aluminum
D Plastic
Iron is commonly used in inductors to increase inductance because it has high magnetic permeability, which allows the magnetic field to be concentrated within the coil, enhancing the inductance.
What is the effect of increasing the cross–sectional area of a coil on its inductance?
A Decreases inductance
B No effect
C Increases resistance
D Increases inductance
Increasing the cross–sectional area of a coil increases its inductance because it allows the magnetic field to spread out more evenly and reduces the reluctance in the magnetic circuit.
How does the length of the coil affect the inductance?
A Increases inductance
B No effect
C Decreases inductance
D Changes capacitance
Increasing the length of a coil decreases the inductance because the magnetic flux is spread over a larger area, increasing the reluctance of the magnetic circuit and reducing the coil’s ability to store energy.
What is the unit of inductance?
A Henry
B Ohm
C Farad
D Tesla
The unit of inductance is the henry (H). One henry is the inductance required to induce a voltage of one volt when the current changes at the rate of one ampere per second.
What does the self–inductance of a coil depend on?
A Only the material
B The current flowing through the coil
C The number of turns and coil geometry
D The voltage across the coil
The self–inductance of a coil depends on the number of turns, the geometry of the coil, and the permeability of the core material. More turns and a larger cross–sectional area increase inductance.
What is mutual inductance in a magnetic circuit?
A Resistance between coils
B Induced current in a neighboring coil
C Self–inductance of a coil
D Power loss between coils
Mutual inductance occurs when a change in current in one coil induces a voltage in a nearby coil. The two coils are magnetically coupled, and the induced voltage depends on the rate of change of current in the first coil.
How does an increase in frequency affect the inductive reactance of a coil?
A Decreases reactance
B No effect
C Decreases current
D Increases reactance
Inductive reactance is directly proportional to the frequency of the signal. As the frequency increases, the inductive reactance increases, which impedes the flow of current in an AC circuit.
What does flux linkage in an inductor depend on?
A Current and the number of turns
B Magnetic field strength
C Temperature
D Voltage across the coil
Flux linkage depends on the current passing through the coil and the number of turns in the coil. More current and more turns increase the amount of magnetic flux linked to the coil, enhancing its inductance.