Ch 18 Magnetism and Electricity

Question 1

what is current electricity.

Answer 1

a steady flow of charge through wires and circuits

Question 2

what is static electricity

Answer 2

involves electric charge collecting in one place and sometimes suddenly jumping from one place to another

Question 3

what is one thing that current and static electricity have in common

Answer 3

they both involve the movement of charged particles

Question 4

what is a conductor and give an example

Answer 4

a substance that allows charged particles to flow through them freely
e.g. conductors

Question 5

what is an insulator and give examples

Answer 5

a substance that doesn’t allow charged particles to flow through them easy
e.g. rubber and plastic

Question 6

what are the electrical wires or a circuit made up of

Answer 6

atoms which contain electrons

Question 7

what is current

Answer 7

the rate of flow of charge per second

Question 8

what is the si unit for electric current

Answer 8

amperes (A)

Question 9

how can you measure current

Answer 9

using and ammeter

Question 10

what are the three effects of electricity

Answer 10

heating, magnetic, chemical

Question 11

explain how a battery transfers energy to electrons and moves them around the circuit

Answer 11

• battery gives energy to electrons
• huh energy electrons drop through the bulb and convert energy to light
• low energy electrons go back to their battery

Question 12

what is potential difference

Answer 12

when there’s a point of high electrical energy and a point of low electrical energy in a complete circuit, we say there’s a difference in potential energy between those two points

Question 13

what is another word for potential difference

Answer 13

voltage

Question 14

what is the si unit for voltage

Answer 14

volts (V)

Question 15

what does a voltmeter do

Answer 15

measured the potential difference across a component

Question 16

what is one “battery” caked on its own

Answer 16

a cell

Question 17

what is a battery

Answer 17

two or more cells stacked together

Question 18

what direction is the flow of electric current in a battery

Answer 18

the flow of electric current is from the positive to the negative side of the battery

Question 19

what are electrodes

Answer 19

two different metals placed in a chemical inside a battery

Question 20

what is an electrolyte

Answer 20

the chemical that the electrodes are in

Question 21

what are the two types of battery’s

Answer 21

a primary cell

a secondary cell

Question 22

what is a primary cell

Answer 22

a battery that can’t be recharged once it’s used

Question 23

what is a secondary cell

Answer 23

a battery that can be recharged and used again

Question 24

what is a series

Answer 24

when components are connected in a single loop with each other and the battery

Question 25

what is a parallel

Answer 25

when components are connected in different branches

Question 26

what do the voltages across all of the different components sum to in a series

Answer 26

they sum to voltage of the battery in the circuit

Question 27

what is resistance

Answer 27

a measure of how difficult it is for an electric current to pass through a substance

Question 28

what is the SI unit for resistance

Answer 28

ohm (the symbol is omega)

Question 29

how is resistance measured

Answer 29

using and ohmmeter

Question 30

how do you calculate current

Answer 30

current (A) = voltage (V) divided by restistance

Question 31

how do you calculate resistance

Answer 31

resistance = voltage divided by current

Question 32

what is resistance used in

Answer 32

appliances some devices need resistors in their circuit boards some devices vary their resistance

Question 33

what are two types of variable resistor

Answer 33

a rheostat | a potentiometer

Question 34

what is a resistor

Answer 34

any component that slows down moving charges

Question 35

how much a resistor slows down the current passing through it depends on:

Answer 35

- length - temperature - nature of material

Question 36

how do you calculate electrical power

Answer 36

electrical power = voltage x current

Question 37

what is alternating current AC

Answer 37

electrons in the wire are constantly changing direction every fiftieth of a second

Question 38

what is direct current DC

Answer 38

flows in one direction only

Question 39

what current do everyday appliances run on

Answer 39

direct current

Question 40

what is a diode

Answer 40

a component that allows current to flow in one direction only

Question 41

what is a forward biased diode

Answer 41

when the positive end of the diode is connected to the negative end of the battery. this allows current to flow

Question 42

what is a reverse biased diode

Answer 42

when the negative end of the diode is connected the to positive end of the battery. no current flows

Question 43

current only flows when it’s forward biased

Answer 43

yuh

Question 44

what is a light emitting diode (LED)

Answer 44

a diode that emits light when current flows through it

Question 45

what is the level of electricity in a live wire and a neutral wire

Answer 45

the live wire has high electrical energy and the neutral wire is low

Question 46

how does the fuse work in a house circuit

Answer 46

if the appliance is faulty the current in the circuit can become too large. the fuse has a thin piece of wire running through it which is designed to melt if the current goes above the set value. when the fuse wire melts, it breaks the circuit and cuts it the electricity. the earth wire draws a large current through the plug and this helps the fuse wire to melt