Photons with energy 5 eV are incident on a cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV When photons of energy 6 eV are incident on C, no photoelectrons will reach the anode A, if the stopping potential of A relative to C is

Option 1 - +3V

Option 2 - +4V

Option 3 - -1V

Option 4 - -3V

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Answered by

Raj Pandey | Contributor-Level 9

4 months ago

Correct Option - 4

Detailed Solution:

According to Einstein's photoelectric equation maximum kinetic energy of photoelectrons, $K E_{max} = E_{v} - φ$

or $2 = 5 - φ$ $∴ φ = 3 e V$

When $E_{v} = 6 e V$ then, $K E_{max} = 6 - 3 = 3 e V$

or $e (V_{c a t h o d e} - V_{a n o d e}) = 3 e V$

or $V_{c a t h o d e} - V_{a n o d e} = 3 V = - V_{s t o p p i n g}$

$∴ V_{s t o p p i n g} = - 3 V$

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