Final answer:
The statement that when electrons release energy, it may be as visible light is true. For the photoelectric effect, visible light is not the only type of electromagnetic radiation that can cause this phenomenon, but rather, light with a frequency above the threshold value for the material.
Step-by-step explanation:
The sentence "When electrons release energy, some of the energy may be released as visible light" is true. Electrons can release energy in the form of electromagnetic radiation when they move from a higher energy level to a lower energy level within an atom. This energy can indeed be in the form of visible light, especially when specific transitions occur within the permissible energy levels of an atom. However, electrons can also release energy as other forms of electromagnetic radiation like infrared or ultraviolet light, depending on the energy difference of the transitions they undergo.
Regarding the photoelectric effect, visible light is not the only type of electromagnetic radiation that can cause this effect. The truth is, different materials have different threshold frequencies above which photoelectric emission can occur. If the frequency of the incoming light is above the threshold value, the excess energy is transferred into the kinetic energy of the ejected electrons, causing them to be emitted from the material.