Circuit

Question 1

3 things for electric circuit

Answer 1

Source of electricity
Device using electrical energy
Complete circuit

Question 2

Electrical conductors

Answer 2

Allow electricity to flow through them

Question 3

Electrical insulators

Answer 3

Don’t allow electricity to flow through them

Question 4

Switch

Answer 4

Open or close a circuit

Question 5

Free electron

Answer 5

Some electrons escape from the atoms and move freely within metal

Question 6

Atom is made of

Answer 6

Nucleus and electrons

Question 7

Electric current

Answer 7

When metal is connected to an electric cell to form a closed circuit, free electrons are driven to flow in a direction from -ve to +ve pole of electric cell

Question 8

Conventional current

Answer 8

+ve to -ve pole

Question 9

Current definition

Answer 9

The number of free electrons flowing through a point in the circuit every second

Question 10

Ammeter

Answer 10

Measurse the size of electric current in amperes

Question 11

Voltage

Answer 11

The amount of energy supplied to the free electron by a source of energy

Question 12

Voltmeter

Answer 12

Measure the voltage

Question 13

Electromagnet

Answer 13

When electric current flows through a coil, coil can attract xx like magnet

Question 14

Resistance

Answer 14

Opposition of material to the flow of electrical current (ohm)

Question 15

Resistance is affected by

Answer 15

Material of wire
Thickness of wire
Length of wire

Question 16

Resistor

Answer 16

Fixed value of resistance, to control or limit the sizes of currents in the circuits of electrical appliances

Question 17

Rheostat

Answer 17

Resistance can be adjusted (rotary-type, sliding)

Question 18

Sliding rheostat format

Answer 18

When sliding contact is moved toward (direction),
Current flows through a (___) length of resistance wire. Resistance is (higher.lower). Current becomes (larger/smaller) and lightbulb becomes (dimmer/brithe)

Question 19

In a series circuit

Answer 19

Current: same
Voltage: different
Resistance: if R1>R2, then V1>V2

Question 20

In parallel circuit

Answer 20

Current: different
Voltage: same
Resistance: if R1>R2, I1<I2

Question 21

Mains electricity

Answer 21

Generated in power stations
Transmitted to homes through electric cables
220V

Question 22

Live wire

Answer 22

Brown
Voltage to drive current flowing through appliance

Question 23

Neutral wire

Answer 23

Blue
Return path to complete circuit

Question 24

Earth wire (green and yellow)

Answer 24

Safety device

Question 25

Domestic circuit

Answer 25

Is connected in parallel so appliances can operate independently

Question 26

Overloading

Answer 26

Connect too many electrical appliances to universal adaptor, current drawn from mains socket is too large. -- very hot and might cause fires or explosion

Question 27

Short circuit

Answer 27

Branch with lower resistance, current becomes very large (e.g. loose wire) -- very hot and might cause fires or explosion

Question 28

Fuse

Answer 28

Protect circuit by breaking the circuit when current is too large. If current flowing through it is too large, the wire becomes hot and melts.

Question 29

Circuit breakers

Answer 29

It has a rating showwing the max current that can flow through. If current exceeds the rating, switch off by itself to break the circuit.

Question 30

Earth wire

Answer 30

Protects users from electric shock by connecting the metal casing of an electrical appliance to the ground. (** THE GROUND)