Wave & Particle Nature of Light

EQ: How can an atom be a "particle" and a "wave" at the same time?

Quantum Concept

Why do heated objects emit only certain frequencies of light?

Temperature of an object is a measure of the average kinetic energy of its particles

As an object gets hotter, it possess a greater

amount of energy and emits different colors of light

Different colors are due to different frequencies and wavelengths

Ground vs. Excited States of e-

Ground State: Lowest energy e- configuration◦Shown on Periodic Table◦Innermost energy level fills first, then work

outward

Ground State vs. Excited State

Excited State: e- can move to a higher energy level without filling the lower energy level first◦Do this by absorbing energy

Excited e- fall back to ground state by releasing energy

Ground State vs. Excited State

The SVP Universal CosmologyA Rosetta Stone for the New Science Paradigm

photon

photon

Photon: Massless particle that carries a quantum of engergy.

Diagram

Elements give off different colors depending on the amount of energy released

(how far the e- falls)

Neon – Ground vs. Excited State

Quantum Concept

German physicist Max Planck established that matter gains or loses energy in small amounts called quantum

Quantum is the minimum amount of energy that can be gained or lost by an atom.

Planck’s mathematical equation for his findings is Equantum = hv

Quantum Concept

Ephoton = hv

Equantum = Energy

h = Planck’s constant (6.626 x 10-34 J s)

v = Frequency

*Note: Joule (J) is the unit of energy

We also need to know………

c = λv

c = Speed of light (3.00 x 108 m/s)

λ = Wavelength (shortest distance between equivalent points on a wave)

ν = Frequency (# of waves that pass a given point per second)

We also need to know………

http://www.google.com/url?sa=i&rct=j&q=electromagnetic+spectrum&source=images&cd=&cad=rja&uact=8&docid=J4O_enDG54gOtM&tbnid=BjGLOSwU7oJOnM:&ved=0CAUQjRw&url=http%3A%2F%2Fguweb2.gonzaga.edu%2Ffaculty%2Fcronk%2FCHEM101pub%2FL05-index.cfm%3FL05resource%3DEM-waves&ei=wscNVNj_F4vGggTY1ICICw&bvm=bv.74649129,d.eXY&psig=AFQjCNFJwVhCqEmhnirCmOTG8J1pZ9x5Kg&ust=1410275136364292

Ephoton = hv

What can we determine from these equations?

As energy of a photon increases, the frequency increases and the wavelength decreases

c = λv v= c / λ

Example:A photon is emitted from an atom with an energy of 5.10 x 10-20 J. What is the wavelength of the photon using correct significant figures?

Ephoton = hv

c = λv

v = Ephoton / hv = 5.10 x 10-20 J / 6.626 x 10-34 J s

v = 7.69695 x 1013 s-1

λ = c / v

λ = 3.00 x 108 m/s / 7.69695 x 1013 s-1

λ = 3.89764 x 10-6 m = 3.90 x 10-6 m

Solve & use correct number of sig. figs. (Rally Coach)

1. Ultraviolet radiation has a frequency of 6.8 × 1015 s-1. Calculate the energy, in joules, of the photon.2. Find the energy, in joules, of microwave radiation with a frequency of 7.91 × 1010 s-1.3. A sodium vapor lamp emits light photons with a wavelength of 5.89 × 10-7 m. What is the energy of these photons?4. One of the electron transitions in a hydrogen atom produces infrared light with a wavelength of 7.464 × 10-6 m. What amount of energy causes this transition?

4.5 x 10-18 J

5.24 x 10-23 J

3.37 x 10-19 J

2.663 x 10-20 J

Solve & use correct number of sig. figs.

1. Find the energy in kJ for an x-ray photon with a frequency of 2.4 × 1018 s-1. (1 kJ = 1000 J)

2. A ruby laser produces red light that has a wavelength of 500 nm. Calculate its energy in joules. (1m = 1 000 000 000 nm)

3. What is the frequency of UV light that has an energy of 2.39 × 10-18 J?

4. What is the wavelength and frequency of photons with an energy of 1.4 × 10-21 J?

Ephoton = hv c = λvEquantum = Energy

h = Planck’s constant (6.626 x 10-34 J s)

v = Frequency

*Note: Joule (J) is the unit of energy

c = Speed of light (3.00 x 108 m/s)

λ = Wavelength

ν = Frequency