When a light source of power P emitting monochromatic light of wa… - Vidyadip

MCQ

When a light source of power $P$ emitting monochromatic light of wavelength $\lambda$ is kept at a distance $r$ from a photosensitive surface of work function $\phi$ and surface area $A$, we will have wrong option :-

A
the maximum energy of emitted photoelectrons as $\frac{hc}{\lambda} - \phi$
✓
the stopping potential needed to stop the fastest photoelectron as $e\left[ {\frac{{hc}}{\lambda } - \phi } \right]$
C
the number of photons striking the surface per unit times as $\frac{{P\lambda A}}{{4\pi hc{r^2}}}$
D
All the above

✓

Answer

Correct option: B.

the stopping potential needed to stop the fastest photoelectron as $e\left[ {\frac{{hc}}{\lambda } - \phi } \right]$

b
$\mathrm{K.E}_{.}=\mathrm{eV}_{0}=\frac{\mathrm{hc}}{\lambda}-\phi$

$\mathrm{V}_{0}=\frac{1}{\mathrm{e}}\left[\frac{\mathrm{hc}}{\lambda}-\phi\right]$

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