A metal emits photoelectrons when yellow light is made to fall on it. Which of the following is correct when the metal is irradiated by a violet light?
Choose one answer.
a. The speed of electrons would increase.
b. The speed of electrons would decrease.
c. The number of electrons emitted would increase.
d. The number of electrons emitted would decrease.
To determine the correct answer, we need to understand the concept of the photoelectric effect. The photoelectric effect is the phenomenon where electrons are ejected from a material when light of a certain frequency or energy is incident on it.
According to the laws of the photoelectric effect:
1. The kinetic energy of emitted electrons depends on the frequency (or color) of the incident light, not its intensity.
2. Increasing the intensity of incident light increases the number of emitted electrons, but not their kinetic energy.
Now, let's analyze the given scenario. The metal emits photoelectrons when yellow light is incident on it. This implies that the metal has a threshold frequency (related to yellow light) required for the photoelectric effect to occur.
When the metal is irradiated by violet light, which has a higher frequency than yellow light, we can conclude that the violet light has sufficient energy to overcome the threshold frequency of the metal. Therefore, the number of electrons emitted would increase.
So, the correct answer is: c. The number of electrons emitted would increase.