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Year Nine Science > Physics1 > Flashcards

Flashcards in Physics1 Deck (30):
1

What are the three magnetic elements?

Iron, Nickel and Cobalt

2

How do "north seeking" poles and "south seeking" interact?

They put force on each other:
-Like poles repel
-Unlike poles attract

3

What are the rules for magnetic field lines?

-They never cross
-Always flow north to south (represented by directioj of arrow)
-Closer magnetic field lines mean stronger magnetic field and hence force
-As you go further away from the magnet, the strength of the magnetic field is weaker and so is the magnetic force

4

What is the neutral point?

The area where there is no resultant magnetic force of field (fields have cancelled each other out)

5

What is high magnetic flux density?

The density of the magnetic field lines

6

How is constant field strength shown?

Parallel field lines

7

Why does earth have its own magnetic field?

Because its core is made of iron

8

Where is Earth's magnetic field strongest and weakest?

-Strongest at poles
-Weakest at equator

9

How does the Earth's magnetic field protect us?

It uses its magnetism to deflect harmful rays and radiation from the Sun

10

How do you increase the magnetism of an electromagnet?

-Increase number of coils per unit length
-Choose a core with a higher permeance (ability of an object to accept and amplify a magnetic field)
-Increase supplied potential difference

11

What is the function of a motor?

To turn electrical energy into kinetic energy

12

What is the process of a motor?

1)D.C. current flows through coils which produces a magnetic field (electromagnet)
2) Magnetic field from electromagnet interacts with the field from the permanent magnet
3) This produces forces on the electromagnet to make it spin on the axle

13

Name the two ways to reverse spin of electromagnet:

-Flow D.C. current the other way around the circuit
-Reverse the direction of the permanent magnet

14

How do you make a motor spin faster?

Increase voltage- increases current- increases magnetic field around EM- increases force- spin faster

15

How is electricity mostly made?

Using a generator/dynamo

16

What is Faraday's law?

A law that states that a PD is induced across a wire (producing an electric current) when a coil of current carrying wire cuts through a magnetic field or a magnetic field is cut through a coil of current carrying wire

17

How do you increase the voltage produces by a generator?

-Use a stronger magnet
-Spin/move the shaft quicker
-Increase amount of coil per unit length

18

What is the cutting of a magnetic field called?

Flux linkage

19

How does a photovoltaic cell work?

Light energy is absorbed by cells. It uses differences in conductivity between the silicon inside it to generate a voltage and currents producing electricity

20

What is the main process of any electricity making plant?

Spin a turbine- spin a generator- step up transformer- electricity to national grid

21

What is a renewable and non-renewable resource?

A renewable resource won't run out. There is an infinite quantity of the resource.
A non-renewable resource will run out. There is a finite quantity of the resource

22

What is a filament lamp?

A lamp that creates light by pushing current through a wire. The wire gets hot and glows, releasing light. The wire is usually tungsten

23

What is the relationship between voltage and resistance in a filament lamp?

As voltage is increased, resistance increases

24

What are conductive metals made up of?

A lattice of ions (atoms that have lost or gained electrons)

25

Define electricity:

Flow of electrical charge due to P.D.

26

Define series circuit:

A circuit with one possible route for current to flow through

27

Define parallel circuit?

A circuit with more than one possible route for current to flow through

28

Define potential difference:

The energy per unit charge lost/ gained between two parts in a circuit. Pushes electrons through a conductor

29

Define current:

The rate of flow of electrons

30

Define resistance:

The measure of the obstacle to the flow of current