The Photoelectric Effect & Atomic Spectra

These flashcards cover key concepts related to the photoelectric effect and atomic spectra as discussed in the lecture notes.

What is the photoelectric effect?

The phenomenon in which electrons are emitted from the surface of a metal upon the absorption of electromagnetic radiation.

What evidence does the photoelectric effect provide?

It provides evidence that light is quantised and carried in discrete packets (photons).

This is shown by the fact each electron can absorb only a single photon This means only the frequencies oflight above a threshold frequency will emit a photoelectron

What happens to photoelectrons when light shines on a metal surface?

Photoelectrons are emitted from the surface of the metal.

What is the photoelectric equation?

E = hf = Φ + ½ mv, where h is Planck's constant, f is the frequency of the radiation, Φ is the work function, and mv is the maximum kinetic energy of the photoelectrons.

What is the work function (Φ)?

The minimum energy required to release a photoelectron from the surface of a metal.

What is the threshold frequency?

The minimum frequency of incident electromagnetic radiation required to remove a photoelectron from the surface of a metal.

What is an electronvolt (eV)?

A unit of energy equal to the energy gained by an electron when it travels through a potential difference of one volt.

How is the relationship between energy and frequency demonstrated?

Energy and frequency of light are directly proportional, E = hf.

What causes the emission of light in atomic line spectra?

When an excited electron in an atom moves from a higher to a lower energy level, emitting a photon with energy corresponding to the difference between these energy levels.

What can be said about the relationship between the size of an energy transition and the wavelength of the emitted photon?

The larger the energy transition, the shorter the wavelength of the emitted photon.