Light striking a metal surface causes electrons to be emitted from the metal via the photoelectric effect. The intensity of the incident light and the temperature of the metal are held constant. Assuming that the initial light incident on the metal surface causes electrons to be ejected from the metal, what happens if the frequency of the incident light is increased? Check all that apply. A. The work function of the metal increases. B. The number of electrons emitted from the metal per second increases. C. The maximum speed of the emitted electrons increases. D. The stopping potential increases.

C. The maximum speed of emitted electrons increase

D. The stopping potential increases

Explanation:

Albert Einstein provided a successful explanation of the photoelectric effect on the basis of quantum theory. He proposed that,

“An electron either absorbs one whole photon or it absorbs none. After absorbing a photon, an electron either leaves the surface of metal or dissipate its energy within the metal in such a short time interval that it has almost no chance to absorb a second photon. An increase in intensity of light source simply increase the number of photons and thus, the number of electrons, but the energy of electron remains same. However, increase in frequency of light increases the energy of photons and hence, the energy of electrons too.”

Therefore, due to this increase in energy of photons, the kinetic energy of emitted electrons also increase. And the increase in kinetic energy follows with the increase in velocity.

Now, the stopping potential is directly proportional to Kinetic Energy of the electrons. Thus, the increase in Kinetic Energy, results in an increase in stopping potential.

Therefore, two options apply here:

C. The maximum speed of emitted electrons increases

D. The stopping potential increases

true tan speed = ang vel x radius