Electricity And Magnetism Flashcards

1
Q

What is A material which easily allows an electric current is

A

an electrical conductor

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2
Q

What is A material which does not allow an electric current is

A

an electrical insulator

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3
Q

Name some good electrical conductors

A

Any metal (some are better than others!), graphite (a form of carbon), salt water

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4
Q

Name some good electrical insulators

A

Wood, plastic (most non-metals in fact)

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5
Q

What instrument is used to measure current?

A

Ammeter

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6
Q

What does an ammeter measure?

A

Current

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7
Q

What is the unit of current and what is its symbol?

A

Amperes A

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8
Q

If I increase the number of cells in my battery the current will…?

A

Increase

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9
Q

When the charge moves through the cell it gains…?

A

Energy

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10
Q

Energy per unit charge is also known as….

A

Potential

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11
Q

What is the unit of potential?

A

Volt V

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12
Q

If I connect more bulbs in series with each other the resistance will…and the current will….

A

resistance will increase and the current will decrease

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13
Q

What is the unit of resistance

A

ohm, Ω

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14
Q

What is a current

A

The amount of charge passing a point each second

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15
Q

At a junction in a circuit what is the important rule to remember?

A

Total current in = total current out

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16
Q

Which poles of a magnet attract each other?

A

The opposite poles (North and South)

17
Q

What happens when like poles of magnets come together

A

They repel

18
Q

Give some examples of magnetic materials

A

Iron steel cobalt nickel

19
Q

Give some examples of non-magnetic materials

A

Plastic wood paper rubber glass

20
Q

Why does the earth have a magnetic field

A

The core of the earth is a rotating ball of Iron

21
Q

What is a magnetic field

A

The region around a magnet where other magnetic materials experience a force

22
Q

How are magnetic fields represented in diagrams?

A

Magnetic field lines

23
Q

How could you visualise the field around a magnet?

A

Iron fillings or using a compass

24
Q

What is the shape of a magnetic field around a wire and how can we tell the direction of the field lines?

A

Circular. Right hand “thumbs up” rule. Thumb points in the direction of the current, the fingers curl in the direction of the field

25
When a current flows in a wire a magnetic field is generated. What do we call this effect?
Electromagnetism
26
Name 3 ways to increase the strength of the magnetic field around a solenoid
"* Increase the current * Increase the number of turns on the coil * Add an iron core"
27
What is one of the major advantages of an electromagnet compared to a permanent magnet
Electromagnets can be switched on and off
28
What is a relay circuit used for
To activate high voltage circuits using low voltage circuits (this protects the user from high currents)
29
List some uses of electromagnets
In relays (e.g. to switch of floodlights or x-ray machines in hospitals), in scrapyards to move parts, maglev trains, in electric motors, in rollercoaster braking