Topic 2 - Controlling And Using Electric Current

Question 0

What is voltage

Answer 0

(Potential difference) - the driving force that pushes the current around

Question 1

What is current

Answer 1

Flow of charge around a circuit

Question 2

Resistance

Answer 2

Anything in the circuit which slows the flow down

Question 3

What happens to the current if you increase the voltage

Answer 3

The more current will flow

Question 4

If you increase resistance, what happens to current

Answer 4

The less current will flow

Question 5

Why do resistors get hot?

Answer 5

Electrons collide with the ions in the lattice.
These collisions give the ions in the lattice extra energy, which is emitted as heat.
This heating effect increases the thermistors resistance, so less current will flow.
If it gets too hot, no voltage will flow.

Question 6

Why does after the light meter in a circuit has been used for a long time, the reading becomes incorrect?

Answer 6

Because the battery voltage has increased

So there is more current than expected

Question 7

Explain what happens if the battery is reversed in a circuit with a diode

Answer 7

Stops working

Because the diode will only conduct in one direction

Question 8

Why are diodes used in circuits?

Answer 8

So that the meter connections are the correct way round

Question 9

Issues of planning to burry nuclear waste

Answer 9

Water causes corrosion/leaks

Transportation of radioactive material

People dont want radioactive substances buried near their houses, so limitation on available locations