In which of the following devices is the principle of photoelectric effect not applicable?
Answer Details
The principle of photoelectric effect refers to the phenomenon where electrons are emitted from a material when light of certain frequencies shines on it. This means that in devices that use the photoelectric effect, the emission of electrons is triggered by light. Therefore, the device that does not use the photoelectric effect is the periscope. A periscope is an optical device that uses mirrors to reflect light and allows a viewer to see objects that are not in their direct line of sight. It does not use any photoelectric material or any process related to the emission of electrons by light.