ib chemistry on electromagnetic spectrum and wave particle duality

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Prepared by Lawrence Kok

Tutorial on Electromagnetic Radiation and Wave-Particle Duality.

Electromagnetic Spectrum

Electromagnetic spectrum ranges from Radiowaves to Gamma waves.- Form of energy- Shorter wavelength -> Higher frequency -> Higher energy- Longer wavelength -> Lower frequency -> Lower energy



Inverse relationship between- λ and fWavelength, λ - long

Frequency, f - low

Wavelength, λ - short

Frequency, f - high



Electromagnetic radiation •Travel at speed of light, c = fλ -> 3.0 x 108 m/s•Light Particle – photon have energy given by -> E = hf•Energy photon - proportional to frequency, f

Inverse relationship between- λ and fWavelength, λ - long

Frequency, f - low

Wavelength, λ - short

Frequency, f - high

Plank constant •proportionality constant bet energy and freq

Excellent video wave propagation Click here to view.

Electromagnetic Wave propagation.

Electromagnetic radiation

Electromagnetic radiation •Moving charges/particles through space •Oscillating wave like property of electric and magnetic field•Electric and magnetic field oscillate perpendicular to each other and perpendicular to direction of wave propagation.

Electromagnetic wave propagation

Click here to view video


Wave




wave

Wave – wavelength and frequency - travel at speed of light



Wave




wave


Violet

λ = 410nm

Red

f = c/λ = 3 x 108/410 x 10-9

= 7.31 x 1014 Hz

E = hf = 6.626 x 10-34 x 7.31 x 1014

= 4.84 x 10-19 J

λ = 700nm

f = c/λ = 3 x 108/700 x 10-9

= 4.28 x 1014 Hz

E = hf = 6.626 x 10-34 x 4.28 x 1014

= 2.83 x 10-19 J



Wave



wave





Wave


Simulation on Electromagnetic Propagatin

Click here to view simulation Click here to view simulation Click here to view simulation


wave




Electromagnetic Wave

Violet

λ = 410nm

Red

f = c/λ = 3 x 108/410 x 10-9

= 7.31 x 1014 Hz

λ = 700nm

f = c/λ = 3 x 108/700 x 10-9

= 4.28 x 1014 Hz

Wavelength – Distance bet two point with same phase, bet crest/troughs – unit nmFrequency – Number of cycle/repeat per unit time (cycles in 1 second) – unit Hz


Violet

λ = 410nm

Red

f = c/λ = 3 x 108/410 x 10-9

= 7.31 x 1014 Hz

λ = 700nm

f = c/λ = 3 x 108/700 x 10-9

= 4.28 x 1014 Hz

Which light wave have higher frequency, if both have same speed reaching Y same time?

Violet light

Y

Red light

X



Violet

λ = 410nm

Red

f = c/λ = 3 x 108/410 x 10-9

= 7.31 x 1014 Hz

λ = 700nm

f = c/λ = 3 x 108/700 x 10-9

= 4.28 x 1014 Hz

Which light wave have higher frequency, if both have same speed reaching Y same time?

Violet light

Y

Red light

X


Click here on excellent video red /violet wave

Light travel same speedRed flippers – long λ - less frequentViolet shoes – short λ - more frequent

Click here to view video energy photon

Quantum Weirdness – Is Light/electron a Wave or Particle?

Pass BIG particles through a 2 slit

Pass waves through a 2 slit

Particle gun

Slit

2 bands Interference patterns of many bands

Click here to view simulation

Quantum particles – small particles, like electrons – Is light/electron a Wave or Particle?




Particle gun

Slit


Pass electron through a 2 slit

Interference patterns of many bands

Does electron behave as

Particles

Waves


Particles /photon •single slit – single band•double slit – double band

Wave •Crest/trough appearing•Double slit – interference behind screen – bright/dark bands





Particle gun

Slit





Particles

Waves


Particles /photon •single slit – single band•double slit – double band

Wave •Crest/trough appearing•Double slit – interference behind screen – bright/dark bands

Principle of wave–particle duality.


Single electron behave like particles but travel like a wave




Particle gun

Slit



Conclusion



Particles

Waves

Waves




Particles

Waves




Particles/photon •single slit – single band•double slit – double band

Waves•Crest/trough appearing•Double slit – interference behind screen – bright/dark bands



Particles

Waves








Particles

Waves


Measuring /observing it- which slit it passes through

Waves

Particles









Particles

Waves



Waves

Particles Particles/photon •single slit – single band•double slit – double band








Principle of wave–particle duality.Wave of possibility.

Single electron behave like particle but travel like a wave



Particles

Waves



Waves

Particles Particles/photon •single slit – single band•double slit – double band





Conclusion

Try to measure it.

Is light a Wave or Particle?

Current measured

Photoelectric effect

Electrons are release (photoelectrons)

Light hits metal



Is Light a Wave or Particle?

VS

Current measured


Wave Theory Particle Theory



Light hits metal

Light – Shows photoelectric effect Shine light to metal Current measured





VS

Current measured



Particle Theory•Light energy comes in tiny packets -photons•Amt energy directly proportional to frequency, E = hf•Red light – low freq – low energy •Blue light – high freq – high energy

Wave Theory•Light energy arrives continuously, regardless of freq•Energy proportional to amplitude•Intensity light – depends on amplitude•Low intensity – low amplitude•High intensity – high amplitude



Light hits metal




Is light a Wave or Particle?Is Light a Particle or Wave?

VSClick here to view video










Wave TheoryParticle Theory

Colour/Frequency light Intensity light Colour/Frequency light Colour/Frequency light








Wave Theory

Low intensity – Low amplitudeHigh intensity –High amplitude

Particle Theory

Red light Low frequency – Low energy

Blue light High frequency – High energy


Light energy arrives continuously, regardless of frequency







If light is Wave•Colour/Intensity of light NOT important !•Regardless of colour/freq/intensity

Shine light LONG enough

If light is Particle•Colour/Frequency of light is important !

Shine RED light Shine BLUE light

Red light Low freq – Low energy

Blue light High freq – High energy

Are electrons released?




Wave Theory

No electrons released

Particle Theory


If light is Wave•Colour/Intensity of light NOT important !•Regardless of colour/freq/intensity

Shine light LONG enough

If light is Particle•Colour/Frequency of light is important !

Shine RED light Shine BLUE light

Electrons are released No electrons released Result!

Red light Low freq – Low energy

Blue light High freq – High energy

Are electrons released?



Stream of light


Stream of photonFixed amt of energy – E = hf Is Light a Wave or Particle?



Stream of light






Stream of light




Click here to view video Click here wave and particle Click here wave and particleClick here wave and particle

Video Is Light a Wave or Particle?

Acknowledgements

Thanks to source of pictures and video used in this presentation

Thanks to Creative Commons for excellent contribution on licenseshttp://creativecommons.org/licenses/

Prepared by Lawrence Kok

Check out more video tutorials from my site and hope you enjoy this tutorialhttp://lawrencekok.blogspot.com

ib chemistry on electromagnetic spectrum and wave particle duality

Education

electromagnetic wave

direction of wave propagation

space oscillating wave

frequency travel

unit hzwhich light wave

waveparticle duality

short frequency

magnetic field electric