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Flashcards in Physics Major Deck (35):
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Resistance

Measure of the DIFFICULTY the charges have in moving through a circuit.

1

What is resistance measured in?

Ohms

2

Factors which affect resistance

Length
Substance
Temp
Thickness

3

High resistance - _______ current

Low

4

Low resistance - ________ current

High

5

As the length of the wire increase, resistance _____

Increases

6

As the thickness increases, the resistance _______

Decreases

7

Highest resistance wife

Nichrome

8

Lowest resistance wire

Gold

9

As the temperature increases, the resistance ?

Increases

10

Conditions for wire to have small resistance

Short, thick, gold, cold

11

Wire to have high resistance

Long, thin, nichrome, hot

12

Advantage of parallel circuits

Independent control of lights ( if one breaks, others still function)

13

Advantages of series circuits

Cheaper
Energy efficient

14

Eg of series lights

Christmas lights

15

Eg of parallel lights

House lights
Car lights

16

Total resistance of resistors in series

All resistance added up

17

Total resistance of Parallel resistors

Total resistance is less than the resistance of the lowest resistor

18

Types of energy

Electrical energy
Kinetic
Heat
Light
Sound

19

Conditions of electrocution

Touching two conductors
Different electrical potentials

20

Active wire

Wire that carries electricity to the house and different parts of the house

21

Neutral wire

Carrys back 0v of electricity to the power station to complete circuit

22

Double insulation

Each wire has two layers of insulation around it

23

When is two pin plug used

Use of appliances with insulating cases

24

When is three pin plug used

Appliances with metal casings

25

Color of active wire

Red or brown

26

Color of neutral wire

Blue or black

27

Color of earth wire

Green or yellow

28

Fuse

Breaks a circuit by melting when a large current passed through it

29

Circuit breaker

Excessive current trips the switch and break circuit

30

Earth wire

Low resistance wire that connects metal frames of electrical appliances to the ground

31

Safety switch

When a large difference in current us detected flowing through the active and current wire, the switch breaks so person isn't electrocuted

32

Cost of electricity can be ccated by

Cost = power x time x 30 cents

33

1kw = W

1000 w

34

What happens when too much current flows in an elect magnetic circuit breaker

Cool creates a large magnetic fis which attracts the iron and breaks circuit