Wavelength – λ – distance between successive points on a wave (crest to crest)

Amplitude – vertical distance fro the midline of a wave to the peak or trough

Frequency - ν – number of waves that pass a point in 1 second Hz = cycles per second

• Speed of a wave u = λ ν

Problem page 248

Calculate the frequency (in Hz) of a wave whose speed and wavelength are 713 m/s and 1.14 m, respectively.

Electromagnetic Spectra

Electromagnetic Spectra

Electromagnetic Spectra

Electromagnetic Spectra

• Electromagnetic waves Travel at the speed of light = 3.00 x 108 m/s or 186,000 mi/s

• ν = c / λ

Problem page 249

What is the wavelength (in meters) of an electromagnetic wave whose frequency is 3.64 x 107 Hz?

Planck’s quantum theory

Quantum – the smallest quantity of energy that can be emitted or absorbed in the form of electromagnetic radiation.

• E = hν

• h = planck’s constant = 6.63 x 10 -34 J s

Planck’s quantum theory

• Energy is always emitted in multiples of hν… 2 hν…. 3 hν

Photoelectric effect

Problem page 252

• The energy of a photon is 5.87 x 10-20 What is its wavelength in nanometers?