Electromagnetism

Question 1

What is an electromagnet?

Answer 1

A solenoid with an iron core.

Question 2

How is an electromagnet made?

Answer 2

When a current flows into a wire, and a magnetic feild is formed around it.

Question 3

What is a solenoid?

Answer 3

A wire coiled up into a spiral shape.

Question 4

What is the motor effect?

Answer 4

The motor effect is when a wire carries a current creating a magnetic field, and it interacts with another magnetic field, this causing a force that pushes the wire at right angles.

Question 5

How do you use Flemings Left Hand Rule?

Answer 5

• Line your forefinger up with the magnetic field lines pointing from north to south.
• Line your second finger up with the current, pointing from positive to negative.
• Line the thumb shows the direction of the motor effect force on the conductor carrying the current

Question 6

How does alternating current create waves in speakers?

Answer 6

1. A current in the coil creates an electromagnetic field
2. The electromagnetic field interacts with the permanent magnet generating a force, which pushes the cone outwards
3. The current is made to flow in the opposite direction
4. The direction of the electromagnetic field reverses
5. The force on the cone now pulls it back in
6. Repeatedly alternating the current direction makes the cone vibrate in and out
7. The cone vibrations cause pressure variations in the air, which are sound waves