Photons of energy 5eV are incident on the cathode. Electrons reaching the anode have kinetic energies varying from 6eV to 8eV. Find the work function of the metal and state whether the current in the circuit is less than or equal to saturation current.

Photons of energy 5eV are incident on the cathode. Electrons reaching

1.	Photons of energy 5eV are incident on the cathode. Electrons reaching the anode have kinetic energies varying from 6eV to 8eV. Find the work function of the metal and state whether the current in the circuit is less than or equal to saturation current.
Answer» `KE_(max)=(5-phi)eV` When electrons are accelerated through 5V, they will reach the anode with energy `=(5-phi+5)eV` `10-phi=8` or `phi=2eV` Current is less than saturation current. This is because if the slowest electron also reached the plate it would have 5 eV energy at the anode, but it is given that the minimum energy is 6 eV.

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Photons of energy 5eV are incident on the cathode. Electrons reaching the anode have kinetic energies varying from 6eV to 8eV. Find the work function of the metal and state whether the current in the circuit is less than or equal to saturation current.

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