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?