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In a particular experiment to study the photoelectric effect, the frequency of the incident light and the temperature of the metal are held constant. Assuming that the light incident on the metal surface causes electrons to be ejected from the metal, what happens if the intensity of the incident light is increased? Check all that apply. The choices are:

a. The work function of the metal decreases.

b. The number of electrons emitted from the metal per second increases.

c. The maximum speed of the emitted electrons increases. The stopping potential increases.

Part B: In another experiment, 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?

Respuesta :

skyluke89

1. b. The number of electrons emitted from the metal per second increases.

In the photoelectric effect, when light is shone on a metallic surface, the photons of the light give energy to the electrons in the metal. Electrons can then be emitted by the surface if they receive enough energy, according to the equation:

[tex]hf=\phi + K[/tex] (1)

where

(hf) is the energy given by the photon, with h being the Planck constant and f the frequency of the photon

[tex]\phi[/tex] is the work function of the metal, which is the minimum energy required to extract an electron from the metal

K is the maximum kinetic energy of the electron

Keep in mind that in the photoelectric effect, 1 photon hits 1 electron only. Now let's analyze the 3 statements:

a. The work function of the metal decreases.  --> FALSE. In fact, the work function of the metal depends only on the properties of the metal itself, so it is not affected by the intensity of the incident light.

b. The number of electrons emitted from the metal per second increases.  --> TRUE. When the light intensity is increased, more photons are shone on the metal, so more photons hit more electrons, and so more electrons in the metal are emitted.

c. The maximum speed of the emitted electrons increases. The stopping potential increases.  --> FALSE. As we see from the equation (1), the maximum kinetic energy of the electrons depends only on the frequency of the incident photon (f), not on the number of photons: therefore, the maximum speed is also not affected by the intensity of the light, and the stopping potential is not affected neither (the stopping potential is equal to the minimum potential necessary to prevent the photoelectrons from escaping the metal)

2) c. The maximum speed of the emitted electrons increases. The stopping potential increases.

In this case, the frequency of the incident light is increased: this means that the incident photons have more energy, therefore they give more energy to the electrons, therefore the electrons will be emitted with larger maximum speed. As a consequence, the stopping potential will also be larger, since a larger potential will be needed to stop the photoelectrons. So the only correct statement is c.

The other 2 statements are wrong because:

a. The work function of the metal decreases.  --> FALSE. In fact, the work function of the metal depends only on the properties of the metal itself, so it is not affected by the intensity of the incident light.

b. The number of electrons emitted from the metal per second increases.  --> FALSE. This depends only on the intensity of the light (number of photons emitted), which in this case does not change.

pstnonsonjoku

When the intensity of the incident light is increased, the number of electrons emitted from the metal per second increases.

What is photoelectric effect?

The term potoelectric effect refers to the fact that electrons are emitted from the surface of a  metal when irraditaed with light of appropriate frequency.

We know that when the frequency of the incident light is increased, the kinetic energy of the emitted electrons is increased. Again,When the intensity of the incident light is increased, the number of electrons emitted from the metal per second increases.

Learn more about photoelectric effect: https://brainly.com/question/1190311

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