In the photoelectric effect, what happens as you increase the frequency of light keeping the same intensity constant?
E=hf, so as you increase the frequency of light, the energy of each photon hitting the metal surface is greater. Thus the electrons liberated from the surface of the metal have a greater maximum kinetic energy.
We also said that the intensity of the light should stay the same. Intensity = Power/Area = (Energy/time)/Area. Given that the energy of each photon is greater with a higher frequency of light, there must be fewer photons hitting the metal surface per unit time in order to keep the intensity constant.
Thus, assuming that initially the photon frequency was above the threshold frequency, increasing the frequency at the same intensity will increase the kinetic energy of the photoelectrons liberated from the metal surface, but also reduce the number of electrons released.
Related Physics A Level answers
All answers ▸A nail of mass 7.0g is held horizontally and is hit by a hammer of mass 0.25kg moving at 10ms^-1. The hammer remains in contact with the nail during and after the blow. (a) What is the velocity of the hammer and nail after contact?
An electron of mass 9.11x10^(-31) is fired from an electron gun at 7x10^6 m/s. What size object will the electron need to interact with in order to diffract?
What is the difference between plastic and elastic collision?
Why does current split between branches of a parallel circuit, but voltage remains the same for each branch?