Light of wavelength ' λ ' which is less than threshold wavelength is incident on a photosensitive material. If incident wavelength is decreased so that emitted photoelectrons are moving with

Question

Light of wavelength ' λ ' which is less than threshold wavelength is incident on a photosensitive material. If incident wavelength is decreased so that emitted photoelectrons are moving with some velocity then stopping potential

TestHub · Accepted Answer

According to Einstein's photoelectric equation, the maximum kinetic energy of emitted photoelectrons is given by

$K_{m a x} = \frac{h c}{λ} - Φ$

where $λ$ is the incident wavelength and $Φ$ is the work function of the material.

The stopping potential $V_{s}$ is related to the maximum kinetic energy by

$e V_{s} = K_{m a x} = \frac{h c}{λ} - Φ$

When the incident wavelength $λ$ is decreased, the term $\frac{h c}{λ}$ increases. Since the work function $Φ$ remains constant for a given material, the maximum kinetic energy $K_{m a x}$ of the photoelectrons increases.

Consequently, the stopping potential $V_{s}$ also increases.

Answer: increases

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