• # question_answer The photoelectric threshold wavelength of a certain metal is 3000$\overset{\text{o}}{\mathop{\text{A}}}\,$. If the radiation of 2000$\overset{\text{o}}{\mathop{\text{A}}}\,$ is incident on the metal A) Electrons will be emitted B) Positrons will be emitted C) Protons will be emitted D) Electrons will not be emitted

 [a] For electron emission ${{\lambda }_{\text{incident}}}<{{\lambda }_{0}}$