Einsteins photon theory Photons corpuscular theory E hf

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Einstein’s photon theory Photons = corpuscular theory E = hf E = Photon energy

Einstein’s photon theory Photons = corpuscular theory E = hf E = Photon energy (Joules) h = Planck’s constant = 6. 626 x 10 -34 Js f = frequency of oscillations (Hz, s-1) v = f v = c = speed of light = 3. 00 x 108 m/s f = frequency (Hz) = wavelength (m)

E = hf, h = 6. 626 E-34 Js v = f E =

E = hf, h = 6. 626 E-34 Js v = f E = Photon energy (Joules) v = c = 3. 00 x 108 m/s f = frequency (Hz) = wavelength (m) Example 1: What is the energy of a 460. nm photon? 4. 3213 E-19 J, 2. 70 e. V

E = hf v = f E = Photon energy (Joules) v = c

E = hf v = f E = Photon energy (Joules) v = c = 3. 00 x 108 m/s f = frequency (Hz) = wavelength (m) Example 2: A photon has an energy of 13. 6 e. V. What is its wavelength? (Remember V = W/q, and 1 e. V is one electron moved through 1 volt) 9. 12371 E-08 m = 91. 2 nm

Ex 1 What is the energy (in J) of a photon with a frequency

Ex 1 What is the energy (in J) of a photon with a frequency of 6. 58 x 1014 Hz? E = hf = (6. 626 x 10 -34 Js)(6. 58 x 1014 s-1) = 4. 36 x 10 -19 J

Ex 2 - What is the wavelength of a photon with an energy of

Ex 2 - What is the wavelength of a photon with an energy of 5. 45 x 10 -18 J? E = hf f = E/h = (5. 45 x 10 -18 J)/(6. 626 x 10 -34 Js) = 8. 23 x 1015 Hz v = f , = v/f = (3. 00 x 108 m/s)/(8. 23 x 1015 Hz) = 3. 65 E-8 m = 36. 5 nm

Ex 3 -What is the energy (in e. V) of a 314 nm photon?

Ex 3 -What is the energy (in e. V) of a 314 nm photon? E = hf = hc/ 1 e. V = 1. 602 x 10 -19 J E = hc/ = (6. 626 x 10 -34 Js)(3. 00 x 108 m/s)/(314 x 10 -9 m) = 6. 33 x 10 -19 J E = (6. 33 x 10 -19 J)/(1. 602 x 10 -19 J/e. V) = 3. 95 e. V 6. 33 x 10 -19 J, 3. 95 e. V

A photon has an energy of 6. 02 e. V. What is its wavelength?

A photon has an energy of 6. 02 e. V. What is its wavelength? (answer in nm) (2) E = hf = hc/ 1 e. V = 1. 602 x 10 -19 J E = (6. 02 e. V)(1. 602 x 10 -19 J/e. V) = 9. 64 x 10 -19 J E = hc/ , = hc/E = (6. 626 x 10 -34 Js)(3. 00 x 108 m/s)/(9. 64 x 10 -19 J) = 2. 06 x 10 -7 m = 206 nm (nm = 1 x 10 -9 m) 206 nm

How many photons per second stream from a 620. nm, 300. m. W laser?

How many photons per second stream from a 620. nm, 300. m. W laser? (2) E = hf = hc/ In one second, a 300 m. W laser emits photons with a total energy of. 300 J E = hc/ , = (6. 626 x 10 -34 Js)(3. 00 x 108 m/s)/(620. x 10 -9 m) = 3. 20613 x 10 -19 J (per photon) # photons = (. 300 J/s)/(3. 20613 x 10 -19 J/photon) = 9. 36 x 1017 photons/sec Hey, that’s a lot! 9. 36 x 1017 photons/sec