Study Notes
The electromagnetic spectrum consists of different types of electromagnetic waves, each with unique properties and uses. These waves are ordered by wavelength and frequency, from radio waves with the longest wavelength to gamma rays with the shortest.
- White light — a mixture of seven colours. Example: Can be separated by a prism into a spectrum.
- Dispersion — the effect of splitting light into its component colours. Example: Occurs when light passes through a prism.
- Electromagnetic spectrum — the range of all types of electromagnetic radiation. Example: Includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.
- Transverse waves — waves where oscillations are perpendicular to the direction of travel. Example: All electromagnetic waves are transverse.
- Radio waves — have the longest wavelengths and are used in communications. Example: Used in radio and television broadcasts.
- Microwaves — used in satellite communications and cooking. Example: Used in microwave ovens.
- Infrared radiation — used in remote controls and thermal imaging. Example: Used in night-vision equipment.
- Visible light — the part of the spectrum visible to the human eye. Example: Emitted by the Sun and light bulbs.
- Ultraviolet waves — can cause skin damage but also used for sterilization. Example: Used in tanning beds and to detect forged banknotes.
- X-rays — used in medical imaging. Example: Used to view bones inside the body.
- Gamma rays — have the highest frequency and are used in cancer treatment. Example: Emitted by radioactive substances.
Exam Tips
Key Definitions to Remember
- White light: A mixture of seven colours.
- Dispersion: The splitting of white light into its component colours.
- Electromagnetic spectrum: The range of all types of electromagnetic radiation.
Common Confusions
- Confusing the order of the electromagnetic spectrum.
- Misunderstanding the relationship between wavelength and frequency.
Typical Exam Questions
- What is dispersion? The splitting of white light into its component colours.
- How do microwaves differ from radio waves? Microwaves have shorter wavelengths and higher frequencies than radio waves.
- What are the dangers of ultraviolet radiation? It can cause skin cancer and eye problems.
What Examiners Usually Test
- Understanding of the order and properties of the electromagnetic spectrum.
- Applications and dangers of different types of electromagnetic waves.