P5 - Mains electricity

Question 1

What is the voltage of the mains domestic electricity supply?

Answer 1

230 V

Question 2

How is mains electricity produced?

Answer 2

In generators using EM induction.

Question 3

Why is AC used instead of DC?

Answer 3

This is where the current alternates. This is easier to generate and simpler to distribute.

Question 4

How does EM induction work?

Answer 4

A magnet is moved in or near a wire. The coil of wire experiences a changing magnetic field, inducing voltage across the ends of the wire to produce a current in the conductor. This is in a standard generator.

Question 5

How will the voltage reverse?

Answer 5

If the magnet is turned in the AC generator, or if the magnet is moved out of the coil. If the North-South polarity is reversed this also reverses voltage.

Question 6

How can the voltage be increased?

Answer 6

Add an iron core, increase speed of rotation, increase the number of turns, or increase magnetic field strength.