Question

Which one of the following is the correct graph between the maximum kinetic energy (\( K_m \)) of the emitted photoelectrons and the frequency of incident radiation (\( \nu \)) for a given photosensitive surface?
\includegraphics[width=0.5\linewidth]{10o.png}

• A.
• B.
• C.
• D.

Hint:

Always check for the presence of a threshold frequency in photoelectric effect graphs, as it marks the minimum frequency required to emit electrons from the material, which should be clearly represented.

Answer 1

The Correct Option is C

The Einstein’s photoelectric equation is given by:
\[ K_m = h \nu - \phi \] This equation indicates that the maximum kinetic energy (\( K_m \)) of the emitted photoelectrons is zero when the frequency of the incident radiation is at or below the threshold frequency. As the frequency increases beyond the threshold frequency, \( K_m \) increases linearly with \( \nu \).
The graph in option (C) correctly represents this relationship: it starts from zero at the threshold frequency and increases linearly thereafter.