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Flashcards in P4 Deck (28):
1

Charge

Measured in coulombs. Can be positive or negative

2

Current

A flow of charge. It tells us about the rate of flow of charge (how many coulombs of charge pass through a point every second). It is measure in amps.

3

Ampere

Unit of current (the same as a coulomb per second)

4

Cell

A store of chemical energy used to drive a current

5

Conductor

A material that conducts electricity well

6

Insulator

A material that conducts electricity badly

7

Electron

Tiny particle that flows around a circuit

8

Series circuit

One in which there are no branching parts to the circuit

9

Static Electricity

An isolated imbalance of charge

10

Circuit breaker

A safety device that stops current flowing if the current is too high. If the current is too large, the electromagnet in the circuit breaker becomes very strong, ans this attracts an iron contact, and causes a gap in the circuit, and makes it stop. It does the same thing as a fuse, but this one can be reset

11

Fuse

A thin piece of wire (usually encased in a cartridge) that burns through or melts if too much current passes through it. A safety device.

12

Dischared

when electrons flow from a charged object to the conductor, and makes the charges equal again

13

Van de Graaff generator

a generator that uses friction to scrape off electrons on to the belt, which are then carried off to the spherical metal cover. The cover is negatively charged, and the electrons stay there as they cannot be conducted through the air. when you touch the generatorm the electrons move onto you. If you are insulated (e.g standing on polystyrene) the electrons can't go anywhere and make you negatively charged

14

Equation for current

Current= charge/time I=Q/t

15

Ammeter

a device that measures electrical current

16

Bulb/lamp

the electric device which provides light

17

Voltmeter

device used to measure voltage

18

Resistor

Reduces current, slows down the current (blocks parts of it).

19

Variable resistor

A controlled resistor (i.e aircon and dimmer lights). Varies the current in circuits

20

Buzzer

A generator device that produces a buzzing sound

21

Motor

converts electric energy to mechanical energy

22

Dangers of damaged insulation

We could be exposed to live wires

23

Dangers of overheated cables

broken or damaged wires will cause parts of the cabel to have higher resistance than others. This will cause the wire to heat up, and potentially melt the insulating plastic and start a fire

24

Dangers of electricity in damp conditions

Water is a good conductor of electricity, so wet cables and electrical equipment pose the risk of electrocution

25

Live wire

The dangerous wire. It is connected to the fuse and is brown in HK

26

Neutral wire

The wire kept at 0 volts. It completes the circuit. It is blue in HK

27

Earth wire

a safety wire (not always present). It is a low resistance path to earth in case of accidents, It is yellow/green in HK

28

Coulomb

The unit we use when measuring charge