ME6 - Electromagnetism Flashcards Preview

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Flashcards in ME6 - Electromagnetism Deck (14):
1

What does a current carrying wire create?

A magnetic field

2

The larger the electric current...

The stronger the magnetic field

3

What does the direction of the magnetic field depend on?

The direction of the current

4

What magnetic field is around a straight wire?

A field made of of concentric circles with the wire in the centre

5

What is the magnetic field around a flat circular coil like?

- Around the centre of the flat circular coil of wire it is similar to that of a bar magnet

- Around the coil there are concentric ellipses (stretched circles)

6

Describe the magnetic field around a solenoid like?

- Strong and uniform inside current carrying solenoid

- Outside the coil it is like a bar magnet (ends of solenoid act as a north and south pole making an electromagnet)

7

What can magnetic materials either be?

Hard or soft

8

Why are magnetic materials like iron considered soft?

It looses its induced magnetism quickly (temporary magnet)

9

Why are magnetic materials like steel considered hard?

The magnetism is kept permanently (permeant magnet)

10

Why is iron used in transformers?

Because of its properties - it needs to magnetise and demagnetise 50 times per second

11

How can you increase the strength of a magnetic field around a solenoid?

Add soft iron core

12

Why are electromagnets far more useful than permanent magnets?

- Turn on and off
- Change the magnetic field strength
- Change the shape of the magnet

13

What is an example of a use of electromagnets?

Lifting metal objects and the electric bell

14

Describe the construction of a electromagnet

Current carrying wire wrapped into coil, wrapped around an iron core