L I G H T R E V I E WM R S . R OS E HC HEM 2015

W H AT I S T H E WAV E L E N GT H A N D F R E Q U E N CY O F L I N E 1 A N D L I N E 2?

E N E R G Y O F W A V E S – I T T A K E S M O R E E N E R G Y T O T R A V E L A T A H I G H E R F R E Q U E N C Y …

Low frequency

High frequency, short wavelength

Amplitude

Amplitude

Low frequency,long wavelength

short wavelength l

What kind of relationship exists between wavelength and frequency?

A) LogarithmicB) QuadraticC) DirectD) Inverse

Rueben’s TubeTones

E L E C T R OMAG NE T IC RA D I AT I ON

Vision

V I S I B L E PA RT O F E M S P E C T R U M

PRISM

Slit

Ray of

White Light

Waves 1/33,000” long

Waves 1/70,000” long

RedOrangeYellowGreenBlue

IndigoViolet

400 nm – 700 nm

V O C A B U L A RY O F A WAV E

Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 324

l

A

?

c = speed of light = 2.998 x 10 8 m/s

(really fast, true for every kind of light!)

Wavelength (m or nm)

FREQUENCY (HZ OR S-1)

Amplitude (m)

F R E Q U E N C Y

O’Connor, Davis, MacNab, McClellan, CHEMISTRY Experiments and Principles 1982, page 166

1 second

Frequency

4 cycles/second = 4 hertz

12 cycles/second = 12 hertz

36 cycles/second = 36 hertz

WAV E S• Wavelength (l) - length of one complete

wave. Common units: m or nm

• Frequency (𝜈) - # of waves that pass a point during a certain time period (usually per second)

Common Units: hertz (Hz) = 1/s = s-1

• Amplitude (A) - distance from the origin to the trough or crest (height of one wave)

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

W H I C H C O LO R O F V I S I BL E L I G H T H A S T H E LO NG E S T WAV E L E N GT H ?

A) YELLOW

B) BLUE

C) RED

D) VIOLET

WH I CH TYPE OF L I GH T H AS M OR E E NE R GY TH AN V I S I BL E L I GH T BU T L E S S E NE R GY TH AN G AMM A RAYS ?

A) RadiowavesB) MicrowavesC) InfraredD) UV rays

REVIEW1) Which color of light (Red or Violet) does wave B represent?

2) Which wave has the lowest frequency?

3) Which wave has the most energy?

4) Which wave has the shortest wavelength?

5) Which wave travels the fastest?

WHAT HAPPENS WHEN RED, GREEN AND V IOLET L IGHT ARE D IRECTED AT A GLOW- IN-THE-DARK SURFACE?

F R I S BEE D EM O! !

Vs.

Vs.

REVIEW

Quantized Continuous

A BSO R P T I O N A N D E M I SS I O N

absorption and emission