Electromagnetism

Question 1

Electromagnet

Answer 1

A magnetically soft metal core made into a temporary magnet by the passage of electric current through a coil surrounding it

Question 2

Uses of electromagnets

Answer 2

Headphones, Loudspeakers, Motors

Question 3

Construction of electromagnets

Answer 3

Consist of a coil of wire wrapped around a magnetically soft core & can be turned on & off

Question 4

Direction of current changing

Answer 4

If the direction of current changes, the direction of the magnetic field changes

Question 5

How to increasing field strength around solenoid?

Answer 5

• Increase current in solenoid
• Increase number of turns on solenoid
• Wrapping solenoid around a magnetically soft core

Question 6

What does an electric current produce in wire?

Answer 6

When a current flows through a conducting wire a magnetic field is produced around the wire

Question 7

Electrmagnetic induction

Answer 7

A voltage is induced in a conducting wire when it moves through a magnetic field or when a magnetic field changes through it

Question 8

Electromagnetism

Answer 8

When an electric current passing though a condutor produces a magnetic field

Question 9

The motor effect

Answer 9

When a current carrying wire experiences a force in a magnetic field

Question 10

Electric motor construction

Answer 10

Consists of a coil of wire inside the magnetic field between 2 magnets

Question 11

Increase strength of motor

Answer 11

• Increase size of current
• Add more turns to coil
• Use stronger magnet

Question 12

Increasing induced voltage

Answer 12

• Moving wire more quickly
• Using stronger magnet
• Increase length of wire inside magnet

Question 13

Fleming’s left hand rule

Answer 13

First finger = field (north to south)
Second finger = direction of current
Thumb = direction of force