Ch 18-2 Electromagnetic Spectrum

Waves of the Spectrum• Waves beyond the visible red end of the color band

is called infrared radiation.

• The full range of frequencies is the electromagnetic spectrum.

• The spectrum includes many types of waves

Radio Waves

• They are used in radio, television, radar and microwave ovens.

• Radios use 2 ways Amplitude modulation and frequency modulation.

• Microwaves are shortest radio waves (1m – 1mm)

• Used in cell phones and to cook food

• Radar is used to determine location and

speed of objects

Other rays

• Infrared rays - have lower frequencies than light (1mm – 750nm) it is used to discover areas of heat differences.

• Visible Light – helps people to see and use colors.

• Ultraviolet rays – higher frequency than light, it is used in medicine and agriculture. Helps your body produce Vitamin D. Lamps made to mimic the sun

Other Rays

• X – Rays – high frequency and high energy which can penetrate matter that light cannot. It is used to take pictures of solid objects.

• Gamma Rays – the shortest wavelengths and highest frequencies in the spectrum so they have the most energy. Used to kill cancer cells, take pics of the brain it is dangerous to people if over exposed.