Electromagnetic Induction Quiz

What is Faraday's Law of Electromagnetic Induction?

• The induced emf in a closed circuit is equal to the rate of change of magnetic flux through the circuit.

• The induced emf in a closed circuit is equal to the resistance of the circuit.

• The induced emf is directly proportional to the resistance of the circuit.

• Faraday's Law states that the induced emf is inversely proportional to the rate of change of magnetic flux.

Define self-inductance and provide an example.

• An example of self-inductance is the resistance of a wire to the flow of current.

• Self-inductance is the property of a coil by which it opposes any change in the current flowing through it. An example is when a current flows through a coil, creating a magnetic field that induces a voltage in the same coil, opposing the change in current.

• Self-inductance is the property of a capacitor by which it opposes any change in the current flowing through it.

• Self-inductance occurs when a magnetic field is generated by a resistor.

Explain mutual inductance and its significance in transformers.

• Mutual inductance has no impact on the efficiency of transformers.

• Mutual inductance is essential in transformers as it enables the efficient transfer of electrical energy between coils without direct electrical connection.

• Mutual inductance is only relevant in electronic circuits, not transformers.

• Transformers can function effectively without mutual inductance.

How is magnetic flux related to electromagnetic induction?

• Magnetic flux causes a decrease in electromagnetic induction

• Magnetic flux is unrelated to electromagnetic induction

• Magnetic flux is only related to static electricity, not electromagnetic induction

• Magnetic flux is related to electromagnetic induction by inducing an electromotive force (emf) in a circuit when there is a change in magnetic flux linked with the circuit.

State Lenz's Law and its implications in electromagnetic phenomena.

• Lenz's Law states that the direction of an induced current in a circuit is such that it has no relation to the change in magnetic flux that produced it.

• Lenz's Law states that the direction of an induced current in a circuit is such that it supports the change in magnetic flux that produced it.

• Lenz's Law states that the direction of an induced current in a circuit is such that it opposes the change in magnetic flux that produced it.

• Lenz's Law states that the direction of an induced current in a circuit is such that it enhances the change in magnetic flux that produced it.

What happens to the induced current when the magnetic field is increased according to Faraday's Law?

• The induced current will stop flowing when the magnetic field is increased.

• The induced current will decrease in the same direction as the increase in magnetic field.

• The induced current will remain constant regardless of the increase in magnetic field.

• The induced current will increase in the opposite direction to the increase in magnetic field.

Describe the concept of back EMF in the context of inductance.

• Back EMF in the context of inductance refers to the voltage induced in a coil due to the change in current flowing through it.

• Back EMF is the resistance encountered by the coil in an inductive circuit

• Back EMF is the capacitance effect observed in inductors

• Back EMF is the current flowing in the opposite direction due to inductance

Differentiate between self-inductance and mutual inductance.

• Self-inductance occurs between two coils, inducing an EMF in each other.

• Self-inductance occurs in a single coil, inducing an EMF in itself, while mutual inductance occurs between two coils, inducing an EMF in each other.

• Mutual inductance occurs in a single coil, inducing an EMF in itself.

• Self-inductance and mutual inductance are the same phenomenon.

How does the direction of induced current relate to Lenz's Law?

• Lenz's Law does not apply to the direction of induced current.

• The direction of induced current is the same as the change in magnetic flux.

• The direction of induced current is random and unpredictable.

• The direction of induced current is opposite to the change in magnetic flux.

A 70 H inductor has s time-dependent current flowing through it over a short period of time as shown in the graph below.What is the magnitude of the emf induced by the inductor at time 𝑡 = 0.2 𝑠?

• 140V

• 0.5V

• 2. 22.5 V

• 2. 67.5 V