On a Common Mistake in the Description of the Photoelectric Effect

Abstract

The photoelectric effect is one of the key experiments taught during first- or second-year university and high school modern physics courses. It is usually the first experiment to introduce light quantization and the concept of photons as “packets of energy.” Here, we want to point out a widespread mistake concerning the interpretation of the saturation current at constant light intensity that is found even in some classic hardback literature. Although this is usually overlooked, it can weaken the conclusions a student can draw from the correct understanding of the experiment.