Three different metals X , Y and Z have work functions 2.2 eV , 3.1 eV and 4.2 eV respectively. When a monochromatic light beam of energy E is incident on these metals, it is observed that photoelectrons are emitted from metals X and Y , but not from metal Z . The possible range of the incident photon energy E is:

Step-by-step solution

For photoelectric emission to occur, the energy of the incident photon must be greater than or equal to the work function of the metal ( E ). Given work functions: _X = 2.2 eV , _Y = 3.1 eV , _Z = 4.2 eV . Since metal X emits photoelectrons: E 2.2 eV . Since metal Y emits photoelectrons: E 3.1 eV . Since metal Z does not emit photoelectrons: E To satisfy all three conditions simultaneously, the incident energy must be at least 3.1 eV (to ensure emission from Y ) but strictly less than 4.2 eV (to prevent emission fr