P2b: Generating electricity

Question 1

How is electricity generated using the dynamo effect? (3)

Answer 1

move a coil (electrical conductor) between the poles of a magnet (through a magnetic field) or move a magnet (the magnetic field) near a coil (electrical conductor)

a voltage is induced, resulting in an electric current then passes through the wire

KE is transformed into electrical energy

Question 2

How can the dynamo effect be increased? (3)

Answer 2

stronger magnets are used

there are more turns on the coil

you move the wire or magnet faster

Question 3

What happens to the polarity of the current if the poles of the magnet are reversed?

Answer 3

it reverses

Question 4

How do simple AC generators work? (2)

Answer 4

coil of wire rotates in a magnetic field between magnets, induces voltage on wire, creating a current

every half a turn the current in the coil swaps direction, creating an alternating current

Question 5

What happens if you turn the coil faster in AC generators

Answer 5

More peaks, higher voltage and higher current

Question 6

How is electricity generated at a thermal power station? (5)

Answer 6

fuel burnt in furnace to heat water to produce high pressure steam

steam spins a turbine

turbine turns generator

generator transforms KE to electrical energy

steam travels to cooling tower; cooled and condensed into water

Question 7

Efficiency equation

Answer 7

efficiency = useful energy output (x 100%) / total energy input