Question

The work function of the metal is X $eV$When the light energy 2X $eV$ is made to be incident on it then the maximum kinetic energy of the emitted photoelectron will be
A. 2 $eV$
B. 2X $eV$
C. X $eV$
D. 3X $eV$

Answer 1

Hint: According to the photoelectric equation, the maximum kinetic energy of the emitted Photoelectron is given by the Einstein Photoelectric equation i.e. E_max = $h\nu - \phi $. By using this formula we will get the required solution.

Complete step by step answer:

As we all know that in the photoelectric effect when light strikes the metal, the electron in the metal get highly energetic to move and it leads to the conduction of the electricity in the circuit
So on taking this into the consideration Einstein gives the equation i.e.
The Einstein Photoelectric equation i.e.
E_max = $h\nu - \phi $ $h\nu - \phi $ ……. (1)
Here
E_max = It represent the maximum energy of the photo electron
$h$ = It represents the Planck constant
$\nu $ = It represents the frequency of the incident light
And
$\phi $ = It gives the value of the work function
It is given that
$h\nu $ = 2X
$\phi $ = X
Hence putting the value in the equation (1)
So,
E_max = 2X – X
Hence the maximum energy of the photo electron is given by
E_max = X $eV$
So the correct answer is given is option (c)
E_max = X $eV$

Note: For the working on the Photoelectric effect, Einstein was honored with the Nobel Prize. The value of the Planck constant $heV$ $h$ = 6.62607015 × ${10}^{-34}$ joule second. The SI unit of the Energy in the case of the Photoelectric effect is electron volt $eV$. Don’t forget to write the units after finding the result.