SQA Higher Physics Practice Exam

The photoelectric effect refers to the phenomenon where electrons are emitted from a material when it is illuminated by light of specific frequencies. This effect is a crucial concept in quantum physics and demonstrates the particle nature of light. When photons, which are particles of light, collide with the electrons in a material, they can transfer sufficient energy to these electrons to overcome the attractive forces holding them in the material. If the energy of the incident light (photon energy) is greater than the work function (the minimum energy required to free an electron from the material), then electrons can be emitted. This means that the frequency of the light must be above a certain threshold for the photoelectric effect to occur. Further, the number of emitted electrons is directly related to the intensity of the light, while the energy of the emitted electrons depends on the frequency of the incoming light. The other options describe unrelated phenomena. Absorption of light refers to the process by which photons are taken up by electrons but does not specifically lead to the emission of electrons. Reflection involves light bouncing off a surface without transferring energy to electrons in a way that results in emission. Deflection of light by a magnetic field pertains to the behavior of charged particles in magnetic fields, which is unrelated to the emission