A photoelectric experiment is performed by separately shining a laser of 450 nm
(blue light) and 560 nm (yellow light) on a metal surface and measuring the
number and kinetic energy of the ejected electrons.
The threshold frequency of
the metal is 6.00•10^14 Hz.
a. Compare the number of electrons ejected from the metal for each of the
lasers when directed at the metal for the same amount of time. Explain
How do you find the number of electrons from all of this? I only know how to solve for wavelength and energy??
To determine the number of electrons ejected from the metal for each laser, we need to understand the principles of the photoelectric effect.
The photoelectric effect refers to the emission of electrons from a material's surface when it is illuminated with light. The effect can only occur when the frequency of the incident light exceeds a certain threshold frequency, which is specific to the material.
In this case, we are given the threshold frequency of the metal as 6.00•10^14 Hz. This means that any light with a frequency lower than this value will not produce the photoelectric effect, regardless of its intensity.
Now, let's analyze the two lasers:
1. Blue Light (450 nm, or 4.50•10^14 Hz):
- The frequency of blue light is lower than the threshold frequency of the metal (6.00•10^14 Hz). Therefore, the blue light will not cause any electrons to be ejected from the metal's surface. Thus, the number of electrons ejected from the metal when exposed to blue light for the same amount of time will be zero.
2. Yellow Light (560 nm, or 5.36•10^14 Hz):
- The frequency of yellow light is higher than the threshold frequency of the metal. This means that the yellow light is capable of causing the photoelectric effect.
- When yellow light is incident on the metal's surface, electrons will be ejected. The number of ejected electrons will depend on the intensity or brightness of the light and the efficiency of the process. However, we are not given this information, so we cannot determine the exact number of ejected electrons.
In conclusion, since the blue light has a frequency lower than the threshold frequency, it will not eject any electrons from the metal. On the other hand, the yellow light, with a higher frequency than the threshold frequency, has the potential to eject some electrons, but we cannot determine the exact number without additional information about the intensity and efficiency of the process.