Electromagnetic Induction and Transformers

These flashcards cover key concepts and definitions related to Electromagnetic Induction and Transformers, essential for exam preparation.

What is electromagnetic induction?

It is the process of generating electricity when a voltage is induced in a conductor or coil as it moves through a magnetic field or when the magnetic field changes.

What is the generator effect?

It is when a potential difference is induced in a conductor that is moving through a magnetic field, creating an electric current.

What factors affect the induced potential difference in a conductor?

Factors include the speed of movement, the number of turns on the coils, the size of the coils, and the strength of the magnetic field.

What does a step-up transformer do?

A step-up transformer increases the potential difference of a power source and has more turns on the secondary coil than on the primary coil.

What is the function of a dynamo?

A dynamo is a device that generates direct current (DC) electricity using a rotating coil in a magnetic field with a split-ring commutator.

Describe the structure of a transformer.

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

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

The iron core is used because it is easily magnetized and allows the changing magnetic field to pass through it.

How does an alternating current affect a transformer?

An alternating current produces a changing magnetic field that induces a potential difference in the secondary coil.

What happens when the orientation of the poles of a magnet is reversed?

Reversing the orientation of the poles alters the direction of the induced potential difference.

What is the ideal transformer equation regarding power?

In an ideal transformer, the input power equals the output power, represented by VP × IP = VS × IS.

Define the term 'alternator'.

An alternator is a type of generator that converts mechanical energy to electrical energy in the form of alternating current.

What happens in a step-down transformer?

A step-down transformer decreases the potential difference of a power source and has fewer turns on the secondary coil than on the primary coil.

Why is it important to transmit electricity at high voltages over long distances?

Transmitting at high voltages reduces the current in wires, thus minimizing energy loss due to heating.

What is the transformer equation relating the primary and secondary coils?

The potential difference ratio is equal to the turns ratio: Vp/Vs = Np/Ns, where V is potential difference and N is the number of turns.

How can you determine the type of transformer from its turns?

If the secondary coil has more turns than the primary coil, it's a step-up transformer; if fewer, it's a step-down transformer.

What is the transformer equation?

The transformer equation relates the primary and secondary voltages and the number of turns in a transformer: \frac{Vp}{Vs} = \frac{Np}{Ns} where $Vp$ is the primary voltage, $Vs$ is the secondary voltage, $Np$ is the number of turns in the primary coil, and $Ns$ is the number of turns in the secondary coil.

What is the function and structure of a transformer?

• A transformer changes the voltage of alternating current (AC).
• It can step up the voltage (increase) or step down the voltage (decrease).
• The transformer conserves overall power during voltage transformation.
• It works on the principle of electromagnetic induction.
• A changing current in the primary coil creates a changing magnetic field.
• This changing magnetic field induces a current in the secondary coil.