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Photoelectric EffectIt would be wise to recall and remember the following equation(s):Speed of a wave: v= fλ?b) Speed of an EMR: c= fλ?c) Energy of a wave/photon: E = hfWhat was Heinrich Hertz experiment and what did it prove?44329358890000What did Einstein suggest had enough energy to knock electrons off a piece of metal? What equation did he use to deduce this?Einstein also noticed that some EMR did not knock off an electron, what part of the EMR spectrum and below it did not knock off an electron?What is the threshold frequency and what is its symbol?What is Einstein’s work function?Work Function Equation where:W =h = fo =Example #1:Determine the threshold frequency of a material with a work function of 10 eV. Using Planck’s constant in JoulesUsing Planck’s constant in eV sExample #2Determine the work function of a metal in Joules if the maximum threshold wavelength is 1.10 x 10-7 m. Describe Milliken’s experiment. Use a drawing if you want to describe how his experiment worked. Photoelectric Formulawhere:hf= W = KEmax = Mass of an electron = Example #3The work function for copper is 4.16 eV. If a wave length of 250 nm hits copper, will that be enough energy to knock off an electron?Example #4The threshold frequency (work function) of silver is 1.14 x 1015 Hz. EMR with a wavelength of 2.50 x 10-7 m strikes a piece of pure silver. Determine the speed of the electrons that are emitted. Mass of an electron is 9.11x 10-31 kg.Example #5Gold has a work function of 4.82 eV. A block of gold is illuminated with ultraviolet light (λ = 160 nm). What is the speed of the electron. Note there are two ways to solve for the value of hf of our equation. Assignment - Page 736 Q 5 – 7 and Page 738 Q 12 – 14 & Handout QuestionsPhotoelectric Effect WorksheetThe photoelectric effect is the name given to the process where light waves striking the surface of a metal frees some electrons and produces an electric current. How is it possible for a light wave to liberate an electron from a piece of metal?What is the energy of a 5.0 x 1014 Hz light in both Joules and eV? A radioactive material emits photons, each having an energy of 1.6 x 10-13 J. Calculate the frequency of the electromagnetic radiation (EMR) emitted by the radioactive material.Calculate the wavelength of the electromagnetic radiation.What is the type of electromagnetic radiation (EMR) emitted by the material?Identify the terms in Einstein’s photoelectric equation, hf = KEmax + W.The surface of sodium metal is exposed to electromagnetic radiation of wavelength 6.5 x 10-7m. This wavelength is the maximum for which photoelectrons are released.Calculate the threshold frequency. What is the work function of this metal in eV and in J. A photon has 3.3 x 10-19 J of energy. What is the wavelength of this photon? What part of electromagnetic spectrum does it come from?Electromagnetic radiation incident on a piece of zinc metal releases energetic electrons from its surface. The metal plate is placed in an evacuated chamber. The energy of each photon (wave) is 2.8eV. The metal has a work function energy of 1.1eV.What does it mean when the work function is 1.1 eV?What is the speed of this photon?What is the KE of these electrons that have been released from the zinc metal?What is the speed of these electrons?What is the lowest frequency of light that can cause the release of electrons from a metal that has a work function of 2.8 eV?The threshold wavelength for emission of an electron from a metallic surface is 500 nm.What is the work function for that particular metal?Calculate the maximum speed of photoelectron produced by:400 nmii. 500 nmiii. 600 nmSodium and silver have work functions of 2.46 eV and 4.73 eV, respectively. If I have a wavelength of 250nm:Is that strong enough to release the electrons from both a piece of sodium and silver?What is the speed of the electrons released from sodium and silver? ................
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