Northern School Physics Polarizer Problem Discussion
The formula for light intensity in terms of photon flux and speed of light can be used to get the mean distance between photons after the polarizer:
I=n⋅h⋅fI=n⋅h⋅f
Where:
II is the light intensity (0.75 W/m2)
The photon flux, or nn, is the number of photons per unit area per unit time.
The Planck constant, hh, is 6.62610346.6261034 J/s.
The frequency of light is ff.
Let us first calculate the frequency of the light using the formula for the speed of light:
c=λ⋅fc=λ⋅f
Where:
Is the wavelength of light (633 nm = 633109633109 m), and cc is the speed of light (31083108 m/s).
Calculating frequency (ff) results in:
f=cλf=λc
Now that the values have been entered, we can determine the frequency:
The intensity formula can then be used to determine the photon flux (n):
[n = frac Ih dot dot f]
Put these values in:
[n = frac](0.75](6.626) times [10-34 cdot = 4.74 times 10-14]
This yields (n approximately 2.83 times 1018) photons/m2/s.
Let us now determine the mean separation (d)) between photons. Since the light is not polarized, the photons are dispersed uniformly throughout the area, allowing us to compute the mean distance using the following formula:
[n = frac 1 A cdot frac N d 2 ]
Where: – A is the area (determined by the diameter D), and A = pi dot frac D2 4
– N is the area’s total number of photons, equal to n times a.
the average distance between photons is denoted by (d).
Getting rid of (d):
The expression “[d2 = fracNn cdot A]”
[d = sqrt(fracN), n, cdot A]
Put these values in:
[d = sqrt frac 2.83 times 1018, pi, dot, dot (4 times 10-3), frac 2.83 times 10-18, dot, dot, frac four times 10-3]
This results in 2.83 meters, or (d about 2.83 times 10-6).
Therefore, following the polarizer, the average separation between photons is 2.83 micrometers.
QUESTION
Description
A helium-neon laser with a power of 0.80 mW emits linearly polarized light with a wavelength of 633 nm and a diameter of 4 mm. The measured intensity after the polarizer is I = 0.75 W/m2 . What is the mean distance between the photons after the polarizer?