Is gamma ray present in a smoke detector?

No, gamma rays are not present in typical smoke detectors. Most smoke detectors use ionization or photoelectric technology, which involves the detection of smoke particles using alpha particles or light, respectively. However, some specialized types of smoke detectors, such as those that use americium-241 as a source, emit alpha radiation, not gamma rays. Gamma rays are associated with nuclear reactions and radioactive decay, which are not involved in standard smoke detector operations.