Physics (AS)·Waves · NSSCAS 2.5
The electromagnetic spectrum
Narrated lesson · press play
The light you can see is just one narrow band of a huge family of waves that all travel at the same speed in free space. In this lesson we state that every electromagnetic wave is transverse and travels at c = 3.0 × 10⁸ m/s in a vacuum, tie the whole family together with the wave equation c = fλ, and then walk through the ordered regions — radio, microwave, infrared, visible, ultraviolet, X-ray and gamma — with their approximate wavelengths, sources, uses and hazards. We work c = fλ across the spectrum, fix the visible range at about 400–700 nm, and see the pattern that as wavelength falls, frequency, energy and danger all rise.
What you'll learn in this lesson
By the end you should be able to (NSSCAS Physics (AS) 2.5):
- State that all electromagnetic waves are transverse waves that travel with the same speed c = 3.0 × 10⁸ m/s in free space (a vacuum)
- Recall and use the wave equation c = fλ across the whole electromagnetic spectrum
- State the principal regions of the electromagnetic spectrum in order — radio, microwave, infrared, visible, ultraviolet, X-ray, gamma — and recall the orders of magnitude of their wavelengths
- Recall that the visible region runs from about 400 nm (violet) to about 700 nm (red)
- State typical sources, properties, uses and hazards of each region of the spectrum
- Explain the pattern that as wavelength decreases, frequency and energy increase, so the shorter-wavelength regions are more ionising and more dangerous
Loading your lesson…
You're watching a free 3-minute preview — create a free account to keep going.