Strength of Electromagnets

# Materials Required

Iron bolts-Thin/Thick/ plastic pipe, copper wire turns (20,40,60), A battery of 2,3,4,5 cells, a switch, shoe nails.

# The Procedure

## Real Lab Procedure

• To make an electromagnet, take the enamelled copper wire and wind it tightly around the iron bolt in the form of a coil. Let it have 20 turns that run parallel to each other.
• Make 2 more electromagnets with 40 and 60 turns.
• Rub the free ends of the wires of each electromagnet with the sand paper to remove the enamel coating.
• Connect the electromagnet with 20 turns to a battery of 2 cells through a switch.
• Place some shoe nails near the end of the bolt and switch on the current.
• Count the number of nails attracted by this electromagnet.
• Switch off the current. Observe that the coil loses most of its magnetism though a few nails may still cling to the electromagnet.
• Repeat this activity with other electromagnets of 40 and 60 turns.
• Instead of an iron bolt, wind 60 turns of enamelled copper wire around a plastic pipe and observe if it acts as an electromagnet.
• Count the number of nails attracted by it.

## Simulator Procedure

• Select the number of turns of wire.
• Select the Number of electric cells.
• Select the core of electromagnet.
• Click on the check box to refer the circuit diagram.
• Drag and drop the copper wire from the top of the iron bolt towards the battery to connect it with the positive end of it.
• Drag and drop the copper wire from the bottom of the iron bolt towards the switch to connect it with one side of the switch.
• Drag and drop the copper wire from battery towards the switch to connect the negative end of it with the other end of the switch and complete the connection.
• Click on the switch to on the circuit.
• Drag and drop the dish containing iron nails towards the bottom of the iron bolt.
• Observe the number of nails attracted.
• Click on the switch to off the circuit and try other combinations to understand the difference in attraction.
• Click on the ‘Reset’ button to redo the experiment with different parameters.

# Observations

• The electromagnet loses its magnetism when the electric current is switched off.
• Larger number of nails are attracted by the electromagnet with more number of turns.
• The electromagnet with plastic core attracted very less number of nails compared to the electromagnet with iron core.

# Conclusion

• An electromagnet can be made by wrapping a wire around a piece of iron and passing current through it.
• The strength of an electromagnet depends upon the number of turns of the wire and the core used to make the electromagnet.