1. Wavelength, Frequency, and Planck’s Constant

2. Formulas 1)E = hf E = energy (Joules J) h = Planck’s constant = 6.63 x 10 -34 J x s f = frequency (Hz) 2) c = fλ c = speed of light = 3 x 10 8 m/s f = frequency (Hz) λ = wavelength (m)

3. Wavelength and Frequency Wavelength: length of wave measured from crest to crest and trough to trough Frequency: number of waves that pass a certain point in a set amount of time

4. Energy in Electrons Excited state: when an electron is heated and moves into a higher energy level Ground state: when an electron returns to it’s normal energy after becoming excited – Electrons give off light when they return to the ground state

5. Energy absorbed by the electron to make it EXCITED !!! Energy lost by the electron to return to its Ground state 

6. Practice Problem A sodium vapor lamp emits light photons with a wavelength of 5.89 × 10 -7 m. What is the frequency?

7. Practice Problem Find the energy for an x-ray photon with a frequency of 2.4 × 10 18 Hz.

8. Practice Problem What is the frequency of UV light that has a wavelength of 2.39 × 10 -9 m?

9. Practice Problem If a laser emits 2.3 x 10 -17 J, what is the frequency of this light?

10. Wavelength and Frequency Relationship (INVERSE) Inverse: opposite (one goes up the goes down)

11. Wavelength and Energy Relationship (INVERSE)

12. Frequency and Energy Relationship (DIRECT) DIRECT: both do the same (both up or both down)