Electricity

Question 1

What is current?

Answer 1

The flow of electric charge around the circuit. Unit= Amps (A)

Question 2

In a single closed loop the current is…?

Answer 2

The same everywhere

Question 3

What is the potential difference?

Answer 3

(Voltage) is the driving force that pushes the charge round

Question 4

What is resistance?

Answer 4

Anything in the circuit that slows the flow down. Unit= ohms

Question 5

What links resistance and current?

Answer 5

The greater the resistance across a component, the smaller the current that flows through it.

Question 6

What is the equation that links charge current and time?

Answer 6

Charge = current x time

Question 7

What is charge measured in?

Answer 7

Coulombs

Question 8

What is the equation that links voltage current and resistance

Answer 8

Voltage= current x resistance

Question 9

What do conductors have?

Answer 9

A low resistance

Question 10

What do insulators have?

Answer 10

A high resistance

Question 11

What is an IV characteristic

Answer 11

Refers to a graph which shows how the current flowing through a component changes as the potential difference across it increased

Question 12

Thermistor Resistance

Answer 12

1) Resistance decreases as temperature increases
2) Is a temperature dependent resistor
3) In hot conditions, the resistance drops
4) In cool conditions, resistance goes up

Question 13

.LDR

Answer 13

1) A resistor that is dependent on the intensity of light
2) In bright light, the resistance falls
3) In darkness, the resistance is highest

Question 14

In a parallel circuit, what does adding a resistor do?

Answer 14

Reduces the total resistance

Question 15

AC=

Answer 15

Main supply

Question 16

DC=

Answer 16

Battery supply

Question 17

Factors of AC supplies

Answer 17

The current is constantly changing direction. they are produced by alternating pd in which the positive and negative ends keep alternating

Question 18

What is the UK main supply

Answer 18

ac 230V, frequency is 50 cycles per second or 50Hz

Question 19

Direct current factors

Answer 19

current that is always flowing in the same direction. Created by a direct pd

Question 20

Why do wires have a outer plastic coating?

Answer 20

Double insulating. Casing is an insualtor so no current conducts to user

Question 21

Neutral Wire

Answer 21

Blue, completes the circuit, 0V

Question 22

Live wire

Answer 22

brown, alternates between a positive and negative voltage (230V)

Question 23

Earth Wire

Answer 23

Green/Yellow takes current to ‘earth’ if there is a fault.

Question 24

What happens if you touch the live wire?

Answer 24

A large pd is produced across your body and a current flows through you. This causes an electric shock

Question 25

Why are wires made out of copper?

Answer 25

Becasue good conductor and flexible

Question 26

What are pins made out of?

Answer 26

Brass because good conductor

Question 27

What is the equation linking power resistance and voltage

Answer 27

power = current x voltage

Question 28

What effect does a current through a wire have on the wire

Answer 28

If the current is too much, the wire will melt.

Question 29

What is the equation linking energy charge and voltage

Answer 29

Energy = charge x voltage

Question 30

What is the equation linking power current and resistance

Answer 30

Power = current squared x resistance

Question 31

What is the national grid?

Answer 31

Distributes electricity via transformers and power lines to home

Question 32

Step up transformer?

Answer 32

increases voltage and is found between power station and power lines

Question 33

Step down transformer?

Answer 33

Decreases voltage and is found between power lines and homes.