2019 PARTICLES AND WAVES Part 2 J. A. Hargreaves Lockerbie Academy February 2019 CONTENT Table of Contents CONTENT TABLE OF CONTENTS CONTENT .................................................................................................... 2 Table of Contents ........................................................................................ 2 CHAPTER 5: WAVE PARTICLE DUALITY ................................................................... 5 Summary of Content .................................................................................... 5 Wave particle duality ................................................................................... 5 Photoelectric Effect ..................................................................................... 6 Observations for this experiment .................................................................. 9 Applications of the Photoelectric effect ............................................................ 14 Photomultipliers ..................................................................................... 14 Photomultiplier operation .......................................................................... 15 Practical 1 The photoelectric effect (demo) ....................................................... 15 Practical 2: Photodiode – photovoltaic mode ....................................................... 15 Tutorial 1 Photoelectric Effect ....................................................................... 16 Tutorial 2: Wave-particle duality .................................................................... 16 Exam Questions ......................................................................................... 19 Exam Answers ........................................................................................ 21 Tutorial 1 Answers ................................................................................... 22 Tutorial 2 Answers ................................................................................... 22 CHAPTER 6: INTERFERENCE AND DIFFRACTION ........................................................ 24 Summary of Content ................................................................................... 24 Superposition of Waves ................................................................................ 24 Interference Patterns ............................................................................... 24 Interference and Path Difference ................................................................. 29 Practical 1- Hearing Interference Patterns ......................................................... 31 Interference of Light ................................................................................... 32 Young’s double slit experiment ....................................................................... 32 Practical 2- Laser interference pattern ............................................................. 34 Practical 3 –Finding the wavelength of light ........................................................ 35 Practical 4- Wavelengths of coloured light ......................................................... 35 Another method for measuring - Diffraction ................................................... 36 Gratings .................................................................................................. 36 Splitting White Light ................................................................................ 37 Differences between a Grating and a Prism ........................................................ 39 Thin film interference: an example of interference ........................................... 39 Tutorial 1- Path Difference ............................................................................ 40 Tutorial 2- Gratings..................................................................................... 40 Tutorial 3 –Interference ............................................................................... 40 Tutorial 4 (SCET) ........................................................................................ 41 Exam Questions ......................................................................................... 44 Tutorial answers: ....................................................................................... 47 Tutorial 1 ............................................................................................. 47 Tutorial 2 ............................................................................................. 47 Tutorial 3 ............................................................................................. 48 Tutorial 4: (SCET) Waves ........................................................................... 48 Exam paper answers ................................................................................ 49 CHAPTER 7: REFRACTION OF LIGHT ..................................................................... 52 Summary of Content ................................................................................... 52 Page 2 of 110 CONTENT Table of Contents Refraction of Light ..................................................................................... 52 Snell’s Law: .......................................................................................... 53 Practical 1: Proving Snell’s Law ...................................................................... 53 Finding the Relationship for Refractive Index ................................................... 53 Refractive Index and Waves- proof (for interest) ............................................... 54 Another way to prove this .......................................................................... 56 Refractive index and frequency of light ............................................................. 56 Refractive index and relationship with v, and f .............................................. 57 Critical angle and total internal reflection ......................................................... 57 Fibre-optic Uses ..................................................................................... 59 Medical Industry ..................................................................................... 60 Other Uses ............................................................................................ 60 Examples .............................................................................................. 61 Refraction Equation Summary ........................................................................ 61 Critical angle equations ............................................................................ 61 Optical Instruments .................................................................................... 62 Tutorial 1: Refraction .................................................................................. 63 Tutorial 2 Refraction with Angles .................................................................... 63 Tutorial 3 Critical Angle ............................................................................... 63 Tutorial 4 Refraction- mixed problems .............................................................. 64 Tutorials (SCET) Refraction of light .................................................................. 65 Exam Questions ......................................................................................... 67 Tutorial Answers: ....................................................................................... 70 CHAPTER 8: INVERSE SQUARE LAW ..................................................................... 74 Summary of Content ................................................................................... 74 Irradiance ................................................................................................ 74 Proving the inverse square law, ...................................................................... 76 The Principles of a Method for showing .......................................................... 76 Light Irradiance ...................................................................................... 77 Practical 1- Inverse Square Law ...................................................................... 77 Practical 2- Inverse square again ..................................................................... 77 Variation of light irradiance with distance from a point source of light .................... 77 Practical 3- LASER Beam diameter & Distance ..................................................... 78 Tutorial 1 Irradiance ................................................................................... 78 Tutorial 2 ................................................................................................ 79 Exam Questions ......................................................................................... 81 Tutorial Answers ........................................................................................ 83 Irradiance and inverse square law ................................................................ 83 Exam Papers .......................................................................................... 83 CHAPTER 9 SPECTRA ...................................................................................... 85 Summary of Content ................................................................................... 85 The Atom ................................................................................................ 85 Quantum Mechanics