Magnetic Effect of an Electric Current

Syllabus tag: KCSE | Physics | Form 2 | Topic 16 Magnetic Effect of an Electric Current

Lesson objectives

By the end of this topic, you should be able to:

• Describe the magnetic field due to a current in a straight wire, loop and solenoid.
• Apply the right-hand grip rule and the maxwell screw rule.
• Describe the electromagnet and factors affecting its strength.
• Explain the motor effect and applications including the electric bell and motor.

Summary

Every current produces a magnetic field around it. For a straight wire the field is a set of concentric circles, and its direction is given by the right-hand grip rule. A solenoid with a soft iron core forms an electromagnet. A current-carrying conductor in a magnetic field experiences a force — the motor effect — given by Fleming's left-hand rule.