Magnetism

Question 1

At which part of a magnet are the magnetic forces strongest ?

Answer 1

The poles of a magnet

Question 2

What happens when two magnets are brought close to each other ?

Answer 2

They exert a force on each other .

Question 3

What type of force is exerted if two like poles of a magnet are brought near each other ?

Answer 3

A repulsive , non contact force

Question 4

What type of forces is exerted if two unlike poles of a magnet are brought near each other ?

Answer 4

An attractive , non-contact

Question 5

What is the difference between a magnet and an induced magnet ?

Answer 5

A permanent magnet produces its own magnetic field
An induced magnet becomes magnetic when it’s placed in a magnetic field .

Question 6

What type of force does induced magnetism always cause ?

Answer 6

A force of attraction

Question 7

What happens when an induced magnet is removed from a magnetic field ?

Answer 7

The induced magnet losses most /all of its magnetism

Question 8

Give four examples of magnetic materials ?

Answer 8

1.Iron
2.Steel
3.Colabt
4.Nickel

Question 9

What is a magnetic field ?

Answer 9

A magnetic field is a region around a magnet where a force acts on another magnet or on a magnetic material.

Question 10

How does the strength of a magnetic field alter as you move further away from the magnet producing it ?

Answer 10

The magnet field strength decrease
the furthermore you move away

Question 11

In what direction does a magnetic field point ?

Answer 11

In the direction that a North Pole would experience a force if placed in a field
From the north seeking pole to the south seeking pole

Question 12

What is produced when current flows through a conducting wire ?

Answer 12

A magnetic field is produced around the wire

Question 13

What determines the strength of the magnetic field around the current-carrying wire ?

Answer 13

The magnitude of the current flowing through the wire
The distance from the wire

Question 14

If the direction of the current-carrying wire placed in a uniform magnetic field is reversed , what happens to the force

Answer 14

The direction of the force is reversed

Question 15

What factors affect the size of the force on a current-carrying wire in the magnetic field ?

Answer 15

The magnitude of the current flowing through the conductor.
The strength of the magnetic field that the conductor is placed

Question 17

What is a solenoid ?

Answer 17

A coil of wire which when current passes through creates a strong magnetic field.

Question 18

What is an electromagnet ?

Answer 18

A solenoid with an added iron core
Adding the iron core increases the strength of the magnetic field

Question 19

What is the motor effect ?

Answer 19

When a force is exerted between magnetic field and a current-carrying conductor in that field .

Question 20

What happens if the conductor is parallel to the magnetic field ?

Answer 20

It will not experience a force if placed.

Question 21

What rule is used to determine the force experienced due to the motor effect ?

Answer 21

Fleming’s Left-hand rule

Question 22

When using Fleming’s left hand rule what does the forefinger represent?

Answer 22

The forefinger points in the direction of the magnetic field.

Question 23

When using Fleming’s left hand rule what does the second finger represent?

Answer 23

The second finger points in the direction of current flow in the conductor

Question 24

What does the thumb represent in Fleming’s left hand rule ?

Answer 24

The thumb represents motion

Question 25

How does an electric motor work ?

Answer 25

A coil of wire carrying a current , is placed in a magnetic field . The forces on the two sides perpendicular to the field experience in opposite directions This causes a rotational effect .

Question 26

Describe the makeup of a basic transformer

Answer 26

A primary coil and a secondary coil of wire wrapped around an iron core

Question 27

Why is iron used as the core for a transformer ?

Answer 27

It is easily magnetised

Question 28

Explain how a transformer works.

Answer 28

An alternating current flows through the primary coil . This is induces a changing magnetic field in the core This changing magnetic induces a current to flow in the secondary coil

Question 29

What can be said about the electrical power input and output a 100 percent efficient transformer?

Answer 29

Electrical power input is equal to electrical power output

Question 30

Why must the current flowing through the primary coil of a transformer be alternating ?

Answer 30

For current to be induced in the secondary coil , the magnetic field in the core must be continuously changing For magnetic field to be changing ,the current in the primary coil must be alternating .