Chapter 7, Problem 47R

To determine

To Describe: The way to build an electromagnet and methods to control its strength.

Explanation of Solution

Introduction:An electromagnet is a temporary magnet created when a current carrying wire is coiled around an iron core.

An electromagnet can be made by wrapping a coil of insulated wire around an iron bar and connecting the wire to a battery. When current flows in the wire, magnetic field is produced and the setup becomes a magnet. One end of the electromagnet becomes north pole, and the other end is south pole. If an iron nail is brought near, the iron bar exerts a magnetic force on it, thereby attracting it.When current is switched off, the iron bar loses its s magnetic properties and the iron nail falls.

The magnetic field strength of the electromagnet can be varied by changing the number of wire loops and by changing the current in the wire.

Conclusion:An electromagnet can be made by wrapping a coil of insulated wire around an iron bar and connecting the wire to a battery.The strength of the magnetic field can be varied by varying the turns of wire to the solenoid or by varying the current in the wire.