Electromagnetic Wave

Properties of Electromagnetic Waves

• Electromagnetic wave can travel in free space.
• They travel in straight lines at a speed of approximately 300000 km/s.
• They are electric, magnetic and transverse in nature.

• Electromagnetic waves are electrically neutral.
• Electromagnetic wave show characteristic of polarization.

Polarisation of Transverse Wave

• A transverse wave can be polarized.
• Plane polarized light will be produced when light travels through a polarizing material like polaroid.
• Polaroid is a type of material that only allows light waves of one plane to pass through. This means that only a portion of the source light gets to pass through the polaroid.

Radio Wave

Source
Electrical oscillating circuit (consists of a capacitor and an conductor connected in series)

Application

• Telecommunications
• Broadcasting: Radio and
• television transmission
• Astronomy study

Microwave

Source
Oscillating electrical charge in a microwave transmitter

Application

• Satellite transmissions
• Radar systems to detect objects (size, form and position)
• Cooking

Infrared Radiation

Source
Hot bodies, the sun and fires

Application

• Night vision
• Thermal imaging and physiotherapy
• Remote controls for TV/VCR
• Heating in physiotherapy
• Thermometer
• Cooking

Visible Light

Source
The sun, hot objects, fires, light bulbs, fluorescent tubes

Application

• Sight
• Photosynthesis in plants
• Photography

Ultraviolet Light

Source
Very hot objects, the sun, mercury vapour lamps

Application

• Identification of counterfeit notes
• Production of fluorescent effects
• Production of vitamin D in the skin
• Sterilisation to destroy germs
• Pest control
• Disinfecting drinking water

X-Ray

Source
X-ray tubes where high energy electrons bombarding a metal plate.

Application

• Radiotherapy
• Radiography (X-ray photograph)
• Detection of cracks in building structures
• Crystallography

Gamma Ray

Source
Radioactive substances

Application

• Cancer treatment
• Sterilisation of equipment
• Pest control in agriculture