Physics 3 – Sept 30, 2016 Do Now: P3 Challenge – Determine what direction each point A - E is moving if the wave is moving to the left. A B C D E

Objectives/Agenda/Assignment 4.3 Wave characteristics Agenda: Polarization Matter Waves Wave- Particle Duality

Polarization Natural light consists of all possible orientations of the plane of oscillation for the electric field of the EMR. Polaroid paper or lenses or plastic allows only one direction of oscillation to pass. The result is polarized light with only one direction of oscillation.

Malus’s Law Passing through one polarizer results in no loss of intensity because the original source is still “visible” through the one direction. If a second polarizer is placed in front of already polarized light, only the portion of first polarized light that is the direction of the second polarizer will pass through. The amount of light intensity passing through is given by Malus’s Law 𝑰= 𝑰 𝒐 𝒄𝒐𝒔 𝟐 𝝑 Where I0 is the incident intensity, I is the resulting intensity and θ is the angle between the two planes of polarization.

Problems If light with an intensity of 20.0 W/m2 is passed through polarizer 1 which is oriented at an angle of 25.0 degrees to the vertical, and then through a second polarizer oriented at an angle of 40.0 degrees to the vertical, what is the transmitted intensity? You decide to use two polarizers to control the intensity of a stage light because your diva is complaining about the lights in his eyes. You place the first piece of polarize paper vertically. At what angle do you need to place the second piece of paper to reduce the light intensity by 15%? A

The Wave Nature of Matter Louis de Broglie posited that if light can have particle properties, matter should exhibit wave properties. http://www.youtube.com/watch?v=DfPeprQ7o Gc Dr. Quantum De Broglie proposed that the relationship between mass and wavelength was p = h mv

Wave particle duality Matter Particles Waves Light Atoms Stoichiometry Lots of experiments!!! Double slit experiment works for beams of electrons!!! Photoelectric effect – Light on metal ejects electrons depending on frequency, not intensity Electromagnetic Radiation Ray diagrams, Reflection, refraction, mirrors, lenses Double Slit Expt – Proves waves

Other Wave-Particle Duality videos https://www.youtube.com/watch?v=J1yIApZtLos Is light a particle or wave TEDEd talk. https://www.youtube.com/watch?v=Hk3fgjHNQ2Q Particles and Waves TEDEd Talk https://www.youtube.com/watch?v=Q_h4IoPJXZw Minute Physics Wave particle duality part 1 https://www.youtube.com/watch?v=_riIY-v2Ym8 Minute Physics Wave particle duality part 2

Exit slip and homework Exit Slip – What’s due? (homework for a homework check next class) p171 #20-24 What’s next? (What to read to prepare for the next class. Read IB 4.4, p172 – 181