Uses of Electromagnetic Waves | Physics for GCSE/IGCSE - Year 11 PDF Download

Uses of Electromagnetic Waves

• Electromagnetic waves have a variety of uses and applications. 
• The main ones are summarized in the table below:

Applications of EM Waves Table

• A summary of the uses and dangers of different EM waves is summarized in the diagram below:

Understanding Microwaves vs. Radio Waves

• Both microwaves and radio waves are parts of the spectrum with shared similarities and applications.
• The primary applications of these waves revolve around wireless communication.
• Contrary to common belief, many technologies like WiFi, radar, mobile phones, and satellite communications utilize microwaves rather than radio waves.
• Microwaves, when at very high intensities, can also serve the purpose of heating objects, as famously demonstrated in a microwave oven.

Infrared

• Infrared light is emitted by warm objects and can be detected using specialized cameras known as thermal imaging cameras. These cameras find applications in various fields such as industry, research, and medicine.
• Some security cameras have the capability to perceive infrared light to some extent, enabling them to see in low-light conditions. Infrared lights are utilized to illuminate areas discreetly, with the illumination being detected by the camera.
• Remote controls feature small infrared LEDs that emit invisible signals to an infrared receiver on devices like televisions.
• Infrared light is more efficient in traveling through fiber optic cables compared to visible light. As a result, most fiber optic communication systems utilize infrared for data transmission.

Visible Light

• Visible light constitutes the only segment of the electromagnetic spectrum that the human eye can perceive.
• The human eye can detect wavelengths ranging from 750 nanometers (red light) to 380 nanometers (violet light).

Ultraviolet and Fluorescence

• Ultraviolet rays are responsible for causing a sun tan, serving as the body's defense mechanism against them.
• When certain substances are exposed to ultraviolet light, they absorb and re-emit it as visible light, a phenomenon known as fluorescence.
• Fluorescence is utilized in various ways, such as marking items with invisible ink, a common security feature on banknotes.
• Fluorescent light bulbs operate based on this principle, emitting visible light through fluorescence.

X-Rays in Medicine

• X-rays find extensive application in medicine, primarily for imaging purposes.
• They can penetrate most tissues but are absorbed by denser materials like bones, creating shadows that can be captured on detectors or film.
  • When exposed to x-rays, the bones absorb the x-rays, leaving a shadow which can be seen using a special x-ray detector or photographic film

Gamma Rays Application

• Gamma rays are hazardous and can be employed to eliminate cells and living tissue.
• This property is beneficial in both identifying and treating cancer. When precisely targeted at cancerous tissue, gamma rays can effectively destroy cancer cells.
• Gamma rays are also used to sterilize food and medical equipment by eradicating bacteria.