Question

1. Besides a magnet, what can create a magnetic field?
2.How is the magnetic field of an electromagnet controlled?
3.How are solenoids and electromagnets used in galvanometers, electric motors, and loudspeakers?
4.How does a ferromagnetic rod inside a solenoid affect the strength of an electromagnet?

in short sentences, 8th grader terms

Answer 1

1. Besides a magnet, moving electric charges make magnetic fields.
Electric current in a wire makes a magnetic field around the wire.
The Earth’s molten iron core also makes a big magnetic field.

2. You control an electromagnet by changing the electric current.
More current makes a stronger field.
Reversing the current reverses the magnetic direction.
Adding more wire coils or using an iron core also changes the strength.

3. Galvanometers: a coil with current turns a pointer to show how strong the current is.
Electric motors: current in coils makes forces that spin the motor.
Loudspeakers: a coil moves a cone when current changes, and the cone makes sound.

4. Putting a ferromagnetic rod (like iron) inside a solenoid makes the field much stronger.
The iron lines up tiny magnetic parts inside it and concentrates the field.
Removing the rod makes the electromagnet weaker.