Electromagnetic Effects - CIE O Level Physics

This set of flashcards covers key concepts and principles related to electromagnetic effects as per the Cambridge O Level Physics syllabus.

What is electromagnetic induction?

Electromagnetic induction is the process by which an electromotive force (EMF) is induced in a conductor when there is relative movement between the conductor and a magnetic field.

What does Lenz's Law state?

Lenz's Law states that the direction of an induced potential difference always opposes the change that produces it.

How can an EMF be induced in a coil of wire?

An EMF can be induced in a coil of wire by moving a magnet through the coil or changing the magnetic field around a stationary coil.

What device uses electromagnetic induction to convert mechanical energy to electrical energy?

An electrical generator.

What is the function of an AC generator?

An AC generator converts mechanical energy into alternating electrical energy.

What is the Right-Hand Dynamo Rule used for?

The Right-Hand Dynamo Rule is used to determine the direction of the induced EMF when moving a wire through a magnetic field.

What happens to the induced EMF when the speed of a magnet moving through a coil increases?

Increasing the speed of the magnet induces a higher magnitude of EMF.

What are the components of a transformer?

A transformer consists of a primary coil, a secondary coil, and a soft iron core.

How does a step-up transformer differ from a step-down transformer?

A step-up transformer has more turns on the secondary coil than on the primary coil, while a step-down transformer has fewer turns on the secondary coil than on the primary coil.

What is Fleming’s Left-Hand Rule used for?

Fleming’s Left-Hand Rule is used to determine the direction of the force on a current-carrying conductor in a magnetic field.

What is a common application of electromagnets?

Electromagnets are commonly used in relay circuits, electric bells, and loudspeakers.

What occurs when two parallel wires carrying current in the same direction are placed near each other?

They will attract each other.

What determines the magnitude of the force per unit length between two parallel conductors?

The amount of current and the length of the wire.

What does it mean if the magnetic field is strongest inside a solenoid?

It indicates that the magnetic field lines are densely packed and uniform within the solenoid, behaving like a bar magnet.

What factor will decrease the magnetic field strength of an electromagnet?

Decreasing the current flowing through the wire.

What principle explains why current flows from positive to negative terminals?

The direction of current is based on the flow of positive charge carriers.

During operation, what effect does the split-ring commutator have in a DC motor?

The split-ring commutator reverses the direction of the current in the coil every half-turn to maintain continuous rotation.

How does increasing the number of turns in a coil affect induced EMF?

Increasing the number of turns in a coil increases the total induced EMF because each turn contributes to the cutting of magnetic field lines.

What is the role of the soft iron core in a transformer?

The soft iron core enhances the magnetic field and ensures efficient induction of EMF in the secondary coil.

What happens to the current direction in a coil if the magnetic field direction is reversed?

Reversing the magnetic field direction will also reverse the direction of the current in the coil.