 Waves & Energy H Ch 5&6

Waves  Vibrating disturbance by which energy is transmitted Amplitude (Wavelength) u = λν

Calculate the wavelength ( ) of yellow light if its frequency ( ) is 5.10 x Hz. Example 1

 What is the frequency ( ) of radiation with a wavelength ( ) of 5.00 x m? What region of the electromagnetic spectrum is this radiation? Example 2

Electromagnetic Radiation c = λν c = 3.0×10 8

 When solids are heated, they emit electromagnetic radiation over a wide range of wavelengths  Atoms and molecules could emit (or absorb) energy in discrete quantities, like small packages or bundles Quantum Theory E = h x Planck’s constant (h) h = 6.63 x J s E = hc / λ Because  = c/λ

 How much energy does a wave have with a frequency of 2.0 x 10 8 Hz? ( h = x J. s) Example 1

 Phenomenon in which electrons are ejected from the surface of certain metals exposed to light  Photon is a “particle” of light Photoelectric Effect h KE e - E = h x

Particle-Wave Duality  Possessing both particle like and wave like properties  Not unique to light, but is also characteristic of all matter including e −

Bohr ’ s Theory e - can only have specific (quantized) energy values light is emitted as e - moves from one energy level to a lower energy level

Spectroscope  Instrument used to measure properties of light over a specific portion of the em spectrum

Emission Spectra

Line Emission Spectrum of Hydrogen Atoms Energize the sample

16

Flame Test

Neon Signs