NEETPhysicsDual Nature of Matter
In a photoelectric experiment, monochromatic light of a constant frequency ( > ₀ ) is incident on a photosensitive surface. Which of the following graphs correctly represents the variation of the maximum kinetic energy ( K_ ) of the emitted photoelectrons with the intensity ( I ) of the incident light?
Options
- AA straight line passing through the origin
- BA straight line with a positive slope and a positive y-intercept
- CA parabola passing through the origin
- DA straight line parallel to the intensity axis with a positive y-intercept
Correct answer
D. A straight line parallel to the intensity axis with a positive y-intercept
Step-by-step solution
According to Einstein's photoelectric equation, K_ = h - ₀ . For a given photosensitive surface and a constant frequency of incident light, the maximum kinetic energy of the emitted photoelectrons is constant. It is completely independent of the intensity of the incident light. Therefore, the graph between K_ (on the y-axis) and intensity (on the x-axis) is a straight horizontal line parallel to the intensity axis, having a positive y-intercept equal to h - ₀ . Answer: A straight line parallel to the intensity axis