Question

The graph of kinetic energy against the frequency \( v \) of incident light is as shown in the figure. The slope of the graph and intercept on X-axis respectively are

• A. Planck's constant, threshold frequency
• B. Work function, maximum K.E.
• C. Maximum K.E., threshold frequency
• D. Planck's constant, work function

Hint:

The slope of the kinetic energy vs frequency graph in the photoelectric effect gives Planck's constant, and the X-intercept gives the threshold frequency.

Answer 1

The Correct Option is A

Step 1: Photoelectric effect graph.
In the photoelectric effect, the kinetic energy of the emitted electrons is plotted against the frequency of the incident light. The equation of the graph is: \[ K.E. = h v - \phi \] where \( h \) is Planck's constant, \( v \) is the frequency, and \( \phi \) is the work function of the material. The slope of this graph is \( h \), and the intercept on the X-axis corresponds to the threshold frequency \( v_0 \), where the kinetic energy is zero.
Step 2: Conclusion.
The slope of the graph is Planck's constant, and the intercept on the X-axis is the threshold frequency, so the correct answer is (A).