Electromagnetic Spectrum

Syllabus tag: KCSE | Physics | Form 4 | Topic 34 Electromagnetic Spectrum

Lesson objectives

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

• State the members of the electromagnetic spectrum in order.
• State the common properties of all electromagnetic waves.
• Describe the production, detection and uses of each type.
• Explain the dangers of the ionising radiations and precautions against them.

Summary

The electromagnetic spectrum runs from radio waves of longest wavelength to gamma rays of shortest. All members are transverse, travel at 3 × 10⁸ m/s in a vacuum, need no medium, and carry no charge. As wavelength decreases, frequency and energy increase, and so does the danger.