Answer:
2.13 x 10^-19 J or 0.53 eV
Explanation:
cut off wavelength, λo = 700 nm = 700 x 10^-9 m
λ = 400 nm = 400 x 10^-9 m
Use the energy equation
Where, K be the work function
K = 2.13 x 10^-19 J
K = 0.53 eV
. a boat can travel in still water. (a) if the boat points directly across a stream whose current is what is the velocity (magni
1 answer:
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Answer:
The wavelength of the light decreases as it enters into the medium with the greater optical density.
The frequency of the light remains constant as it transitions between materials.
Explanation:
- When a ray of light crosses a boundary between two different materials, it undergoes refraction: the ray changes direction, and it also changes speed, according to the relationship:
where v is the speed of the ray of light in the material, c is the speed of light in a vacuum, n is the index of refraction of the material, which is larger for a medium with larger optical density. So, from the equation, we see that the larger the optical density, the smaller the speed of the wave.
- The frequency of the light does not depend on the properties of the medium, so it remains unchanged: therefore the statement
The frequency of the light remains constant as it transitions between materials.
is correct.
- Moreover, the wavelength of the ray of light is related to the speed and the frequency by the equation
where v is the speed and f the frequency. Since we have seen that v decreases and f remains constant, this means that the wavelength decreases as well, so the statement
The wavelength of the light decreases as it enters into the medium with the greater optical density.
is also correct.