8.3 Electric Current

Question 1

Structure of atom
Charge

Answer 1

Nucleus (+) surrounded by electrons (-)

Question 2

What are free electrons

Answer 2

Electrons that escape fr atoms and move freely within metal

Question 3

What forms electric current

Answer 3

Flow of free electrons

Question 4

Free electrons direction
Electric current direction

Answer 4

Electrons: - —> +

Current: + —> -

Question 5

Current +—> - , this is called the _____

Answer 5

Conventional current

Question 6

What measures current, unit

Answer 6

Ammeter, ampere (A)

Question 7

Positive negative terminal colours

Answer 7

Positive red
Negative black

Question 8

How to connect ammeter

Answer 8

Current flows into positive, leaves fr negative
加連加 減連減

Question 9

power supply , connecting wire, nichrome wire and wax, connecting wire, ammeter, connecting wire
What happens to wax and nichrome wire
Energy conversion

Answer 9

Wax melts
Nichrome wire red,hot,glows
Electrical, thermal and light

Question 10

Wire when electrical->thermal
What is this effect called

Answer 10

Wire heats up
Heating effect of current

Question 11

Relationship between current and heating effect

Answer 11

Larger current, larger heating effect

Question 12

show magnetic effect
Electromagnet

Answer 12

Current-carrying wire affects direction of needle of compass
Current-carrying coil acts like magnet

Question 13

Why electromagnet useful
Examples

Answer 13

like magnet that can be switched on/off
magnetic effect only when current flows

Electric door lock,, electric bells