SP10/11 - Electricity and Cicuits

Question 1

Which way does the conventional current flow?

Answer 1

From the positive terminal to the negative terminal

Question 2

What do all metals contain?

Answer 2

‘Free’ electrons

Question 3

What is a series circuit?

Answer 3

When there is one route the current can take around the circuit

Question 4

What is a parallel circuit?

Answer 4

When there are junctions that allow the current to take different routes

Question 5

What is current?

Answer 5

The rate of flow of charge

Question 6

What is the unit for current?

Answer 6

Amperes (Amps)

Question 7

What is used to measure the current?

Answer 7

Ammeter

Question 8

What is potential difference?

Answer 8

The amount of energy transferred per unit of charge

Question 9

What is the unit of potential difference?

Answer 9

Volts

Question 10

What is used to measure potential difference?

Answer 10

Voltmeter

Question 11

What is the rule for current in a series circuit?

Answer 11

Current is the same everywhere

Question 12

What is the rule for current in a parallel circuit?

Answer 12

The current is different everywhere

Question 13

What is the unit for charge?

Answer 13

Coulombs

Question 14

What is the formula for current?

Answer 14

charge
current = ————-
time

Question 15

What is the formula for potential differnce?

Answer 15

energy
potential difference = ————
charge

Question 16

What is resistance?

Answer 16

A measure of how hard it is for current to flow

Question 17

What is the unit for resistance?

Answer 17

Ohms

Question 18

What is the formula for resistance?

Answer 18

potential difference
resistance = ——————————–
current

Question 19

Study rules for series circuits

Answer 19

Study rules for parallel circuits

Question 20

What is a LED?

Answer 20

Light Emitting Diode

Question 21

How does a thermistor work?

Answer 21

The resistance changes with temperature
High temperature = resistance decreases
Low temperature = resistance increases

Question 22

How does a Light Dependent Resistor work?

Answer 22

The resistance changes with light
Dark = resistance increases
Light = resistance decreases

Question 23

What is power (electrical)?

Answer 23

The amount of energy transferred each second

Question 24

What are the 2 formulas for power?

Answer 24

power = current x potential difference
power = (current)^2 x resistance

Question 25

What does DC and AC stand for?

Answer 25

Direct current Alternating current

Question 26

What is direct current?

Answer 26

When the current doesn't change direction (stays positive) and flows in one direction

Question 27

What is alternating current?

Answer 27

When the current changes (switches between positive and negative) and flows in both directions

Question 28

What are the three wires that are found in a plug?

Answer 28

Live wire Neutral wire Earth wire

Question 29

What colour is the live wire?

Answer 29

Brown

Question 30

What colour is the neutral wire?

Answer 30

Blue

Question 31

What colour is the earth wire?

Answer 31

Green / Yellow

Question 32

What is the potential difference of the live wire?

Answer 32

230V

Question 33

What is the potential difference of the neutral wire?

Answer 33

0V

Question 34

What is the potential difference of the earth wire?

Answer 34

0V

Question 35

How do the earth wire and fuse stop the plug from being a safety hazard?

Answer 35

If the live wire touches the metal casing. The earth wire draws the current to the earth, stopping the appliance from being live and increasing the current because of less resistance. The increase in current causes the fuse to heat up and melt, breaking the circuit.

Question 36

What are circuit breakers?

Answer 36

Devices that cut off the current if the current becomes too high.

Question 37

What are Residual Current Devices?

Answer 37

A type of circuit breaker

Question 38

What are the advantages of circuit breakers over fuses?

Answer 38

Fuses have to be replace whereas circuit breakers can be switched back on again.