Topic 2-Electricity Flashcards Preview

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Flashcards in Topic 2-Electricity Deck (73)
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1

What is an electric current?

A flow of charge.

2

What is the unit of current?

Ampere.

3

If it is a single closed circuit what is the current like?

It is the same everywhere in the circuit.

4

What is the potential difference?

The driving unit which pushes the charge around.

5

What is the unit of potential difference?

Volts.

6

What is resistance?

Anything that slows the force down.

7

What is resistance measured in?

Ohms.

8

What is the relationship between resistance and current?

The greater the resistance ,the smaller the current that flows.

9

How do you work out charge flow?

Charge flow=current x time

10

How do you work out potential difference?

Potential difference=Current x resistance.

11

What does an ammeter measure?

The current.

12

What does the voltmeter measure?

Potential difference.

13

For diodes what does the resistance depend on?

The direction of the current.

14

Does the resistance of an rhombic conductor change?

No.

15

What does LDR stand for?

Light dependent resistor.

16

What is an LDR dependent on?

The light intensity.

17

For an LDR in a bright light what happens to the resistance?

It falls.

18

For an LDR in darkness what happens to the resistance?

It is at its highest.

19

What are LDRs used for?

Burglar detectors and automatic night lights.

20

What is a thermistor dependent on?

Temperature.

21

In hot conditions what happens to the resistance of a thermistor?

It drops.

22

In cool conditions what happens to the resistance of a thermistor?

It goes up.

23

What can thermistors be used for?

Car engine temperature detectors and electronic thermostats.

24

What can sensing circuits be used for?

To turn on or increase the power to the components depending off the conditions they are in.

25

In series circuits is the current shared equally through all components or is it the same current as the total?

The same current as the total.

26

In series circuits is the potential difference shared?

Yes.

27

If you remove a component in a parallel circuit will it most likely affect the other components?

No.

28

If you add a resistor to a parallel circuit what happens to the resistance?

It reduces it.

29

What two types of electricity supplies are there?

Alternating current and direct current.

30

What is the current like in an alternating current supply?

It constantly changes direction.