Ch. 19 - Light

I. Electromagnetic Radiation (p.528-535)

EM RadiationEM SpectrumTypes of EM Radiation

A. EM Radiation

Electromagnetic Radiationtransverse waves produced by the motion of electrically

charged particlesdoes not require a mediumspeed in a vacuum = 300,000 km/selectric and magnetic

components are perpendicular

A. EM Radiation

Photonstiny, particle-like

bundles of radiationabsorbed and released

by electronsenergy increases with wave

frequency

B. EM Spectrum

long

low f

low energy

short

high f

high energy

C. Types of EM Radiation

Radiowaveslowest energy EM radiation

C. Types of EM Radiation

RadiowavesFM - frequency modulation AM - amplitude modulation

Microwavespenetrate food and vibrate

water & fat molecules to produce thermal energy

C. Types of EM Radiation

Infrared Radiation (IR)slightly lower energy than

visible lightcan raise the thermal energy

of objectsthermogram - image made by

detecting IR radiation

C. Types of EM Radiation

Visible Lightsmall part of

the spectrum we can see

ROY G. BIV - colors in order of increasing energy

R O Y G. B I V

red orange yellow green blue indigo violet

C. Types of EM Radiation

Ultraviolet Radiation (UV)slightly higher energy than visible lightTypes:

• UVA - tanning, wrinkles• UVB - sunburn, cancer• UVC - most harmful,

sterilization

C. Types of EM Radiation

Ultraviolet Radiation (UV)Ozone layer depletion = UV exposure!

C. Types of EM Radiation

X rayshigher energy than UVcan penetrate soft tissue,

but not bones

C. Types of EM Radiation

Gamma rayshighest energy

EM radiationemitted by

radioactive atomsused to kill

cancerous cells Radiation treatment using radioactive cobalt-60.