Einstein's 1905 paper on the photoelectric effect was the first important application of Planck's quantum hypothesis. Describe Planck's original hypothesis, and explain how Einstein made use of it in his theory of the photoelectric effect.

Video transcript

hey everyone in this example, we need to identify which statement below is an incorrect statement. So looking at statement one, we're told that the Plank's original hypothesis was that energy could only be gained or lost in discrete amounts. Quanta with a certain minimum size. And we should recognize that this is actually a true statement. Because we want to recall that the size of our minimum energy change is going to be directly related to our frequency of radiation that is absorbed or emitted. And we're going to divide this in this formula by Plank's constant. So we should recognize that this formula is a formula for the quantization of energy. So moving on to statement two, we have the statement saying that Einstein postulated that light itself is quantized. And what this is stating is that when we think of the speed of light, we should recall that when we're solving problems we always state that the speed of light is equal to a value of 3.0 times 10 to the eighth power with units of meters per second. And because we associate the speed of light with this value, it is definitely quantized. So we would say that this is going to be there for a true statement. Moving on to statement three, we are told that if the photon has energy that is less than the threshold energy an electron is emitted and any excess energy becomes the kinetic energy of the electron. We should correct this statement to say that the photon should have energy that is either greater than or equal to the threshold energy And then it would be a true statement. But because it doesn't say this, we would say that this statement is false. So so far we have ruled out choices one and two and that means choice three is definitely a correctly or a answer choice. That we can confirm is correct here because it is an incorrect statement. So moving on to the last statement, we're told that if a photon that strikes a metal surface has more than the threshold energy, no electron is emitted from the surface. Now we also need to correct this statement because the photon should have more energy. Or sorry, less energy here and then our threshold energy. And so we would also confirm that choice four is another correct choice to complete this example as an incorrect statement. So the only answer choices to complete this example as our final answer. Our choices three and four which were both false statements that we had to correct. So I hope that everything I explained was clear. If you have any questions, just leave them down below and I will see everyone in the next practice video