Investigating the Strength of Electromagnets

Investigating the Strength of Electromagnets

Aim:

To investigate into the effect that changing the number of turns on

the coils has on the strength of an electromagnet.

Background Information:

If an electric current flows through a coil of wire a magnetic field

is formed around the coil, creating an electromagnet. This is a

temporary magnet, which can be switched off. There are three ways in

which you can increase the strength of an electromagnet:

Ÿ Increase the number of turns on the coil.

Ÿ Increase the size of current flowing, have more cells or increase

voltage.

Ÿ Place a soft iron core inside the coil.

There are many variables that could effect the strength of the

electromagnet:

Ÿ The current/ voltage

Ÿ The soft iron core

Ÿ The length of the piece of copper wire used for the coils.

Ÿ Number of paperclips /size.

Ÿ Time for the electromagnet to attract the paperclips.

Ÿ Leads used

In my experiment I will be increasing the amount of turns in the coil.

I will use a coil with 20, 40, 60 80 and 100 turns.

Diagram:

Equipment list:

Power pack,

Leads,

Iron core,

Copper wire,

Paper clips,

Ammeter,

Thermostat,

Stop Watch.

Investigating the strength of electromagnets(2)

Method:

I will set the apparatus as shown in the diagram above and then turn

the power pack on to Volts. Using my first coil, which has 20 turns, I

will put the electromagnet on the paperclips (100) laid on the table

and start the stop watch. I will leave the electromagnet there for 30

seconds. Next I will lift the magnet and move it away from the

paperclips that are not attracted to the magnet. Then I will switch

the electromagnet off and count and record the number of paperclips

that were still attracted to the magnet.

I shall then repeat the above only changing the number of turns on the