Electromagnetic waves are transverse waves that travel with the same speed in a vacuum. They can travel through a vacuum. They do not require any medium to travel from one point to another. Electric and Magnetic Fields: Electromagnetic waves consist of oscillating electric (𝐸) and magnetic (𝐵) fields. These fields oscillate perpendicular to each other and to the direction of wave propagation.
All electromagnetic waves travel at the same speed in a vacuum, denoted by 𝑐. This speed is $3.0 \times 10^8 \text{ m/s}$.
The main regions of the electromagnetic spectrum in order of wavelength and frequency are as follow:
| Region | Wavelength | Frequency | Typical Uses |
|---|---|---|---|
| Radio Waves | > 1 m | 108 Hz | Radio and television communication, astronomy, RFID tags |
| Microwaves | 1 mm to 1 m | 1011 Hz to 108 Hz | Mobile (cell) phones, microwave oven, satellite television |
| Infrared | 700 nm to 1 mm | 4.3 × 1014 Hz to 1011 Hz | Infrared remote controllers, intruder alarms, thermal imaging |
| Visible Light | 400 nm to 700 nm | 7.5 × 1014 Hz to 4.3 × 1014 Hz | Photography, optical fibres in medicine and telecommunications |
| Ultraviolet | 10 nm to 400 nm | 1016 Hz to 7.5 × 1014 Hz | Sunbeds, bank note authentication, disinfecting water |
| X-rays | 0.01 nm to 10 nm | 1019 Hz to 1016 Hz | Medical radiology, security screening, industrial defect detection |
| Gamma (γ) Rays | 0.01 nm | > 1019 Hz | Sterilising food, detection of cancer and its treatment |
Over-exposure to electromagnetic waves can have various hazardous effects on living cells and tissues due to heating and ionizing effects.
High-frequency electromagnetic waves, such as X-rays and gamma rays, possess enough energy to ionize atoms and molecules. This ionizing radiation can cause significant damage to living cells and tissues.