My textbook goes on explaining variations of photo current/stopping potential and frequency/intensity of the light used.
My doubt is what effect does the amplitude of light wave have on photo current and stopping potential?
The intensity of a wave is directly proportional to the square of the amplitude of the wave. Mathematically speaking, $I \propto a^2$. So, increasing the amplitude increases the intensity of the wave. And the increase in intensity of the incident radiation increases the number of photo-electrons, but it does not affect the stopping potential of the concerned metal surface.