Electromagnetism

Question 1

Describe how a current running through a wire generates a magnetic field.
And also what effects the magnetic field around a wire

describe how the magnetic effect of a current can be
demonstrated

Answer 1

When a current flows through a conducting wire a magnetic field is produced around the wire. The strength of the magnetic field
depends on the current through the wire and the distance from the wire (As you get close t the wire the magnetic field increases.)

Also if we change the direction of the current we change the direction of the magnetic field

Question 2

• draw the magnetic field pattern for a straight wire carrying a current and for a solenoid (showing the direction of the field)

Answer 2

To figure out the direction of the magnetic field for a wire with a current we use The Right hand Grip Rule.

We place our right hand so that our thumb is facing the direction of the current (wire) and now the fingers are pointing in the direction of the magnetic field

Question 3

Describe the magnetic field of a solenoid

Answer 3

Shaping a wire to form a solenoid increases the strength of the magnetic field created by a current through the wire. The magnetic field inside a solenoid is strong and uniform.
The magnetic field around a solenoid has a similar shape to that of a bar magnet

Question 4

Explain the ways that we can increase the strength of the magnetic fields of a wire/solenoid

Answer 4

1. If we increase the size of the current, then we increase the size of the magnetic field
2. The strength of the magnetic field increases if we increase the number of turns on the coil (solenoid)
3. If we place a piece of iron ( An iron core) inside the solenoid, then we increase the strength of the magnetic field.

Question 5

what is an electromagnet?

Answer 5

An electromagnet is a solenoid with an iron core.

Question 6

Explain why electromagnets are useful

Answer 6

Electromagnets are useful because we can change the strength of the magnetic field by changing the size of the current. varying the force (e.g. in aloudspeaker)
And we can also turn electromagnets on and off.

Question 7

Students should be able to interpret diagrams of
electromagnetic devices in order to explain how they work.