De Broglie's and Photoelectric Effect

[Simrina Desar Dis 1H]

In question 1.33 how would you differentiate between using the kinetic energy formula and De Broglie's equation?

[Rachel Lu_dis1H]

You use DeBroglie's equation in part a when finding the wavelength of the ejected electron
You would use the kinetic energy formula in part C to help you find the energy of the photon. E(photon) - threshold energy = E(kinetic) You plug in mass of an election and the velocity into the kinetic energy formula. Once you find the kinetic energy, you can plug E(kinetic) and the threshold energy back into the E(photon) - threshold energy = E(kinetic) equation to find E(photon).

[Kevin Liu 3G]

For any question, it depends on what you're looking for. De Broglie's equation connects wavelength, mass, and velocity whereas Ek connects energy, mass, and velocity. So in some questions you need both but the key point is that one equation can help you find wavelength, whereas the other one helps you find energy.