Physics IG electromagnetic spectrum

IGCSE

Radio Waves uses (3)

Radio and television transmissions, astronomy, radio frequency identification (RFID).

Microwaves uses (3)

Satellite television, mobile phones (cell phones), microwave ovens.

Infrared uses (5)

Electric grills, short range communications such as remote controllers for televisions, intruder alarms, thermal imaging, optical fibres.

Visible Light uses (3)

Vision, photography, illumination.

Ultraviolet uses (3)

Security marking, detecting fake bank notes, sterilising water.

X-rays uses (2)

Medical scanning, security scanners.

Gamma Rays uses (2)

Sterilising food and medical equipment, detection of cancer and its treatment.

Microwaves drawbacks(1)

Internal heating of body cells.

Infrared drawbacks (1)

Skin burns.

Ultraviolet drawbacks (2) with consequences

Damage to surface cells and eyes, leading to skin cancer and eye conditions.

X-rays and Gamma Rays drawbacks(2)

Mutation or damage to cells in the body.

Some satellite phones and direct broadcast satellite television

Geostationary satellites

Other satellite phones use

Low orbit artificial satellites

What electromagnetic radiation do cell phones and wireless internet use? Why?

Microwaves because microwaves can penetrate(go through) some walls and only require a short aerial(antennae) for transmission and reception(receiving)

What electromagnetic radiation do bluetooth use? Why?

Radio waves can pass through walls but the signal is weakened on doing so

What electromagnetic radiation do optical fibres use? Where?Why(2)?

Visible light or Infrared are used for cable television and high-speed broadband because glass is transparent to visible light and some infrared AND visible light and short wavelength infrared can carry high rates of data

Difference between digital and analogue signal

Analogue signal varies continually in amplitude and frequency

Digital signals consists of a series of pulses which are either on or off

Benefits of digital signalling(2)

increased rate of transmission of data
increased range due to accurate signal regeneration