Intensity of Light With a Given Power of Through a Polarizer

The intensity of the laser beam after passing through the polarizing filter can be calculated by taking the initial power of 200 mW and multiplying it by the cosine squared of the angle between the polarization direction and the filter axis, which in this case is 25 degrees. This results in an intensity of approximately 180 mW. In summary, the power of the laser beam after passing through the polarizing filter is 180 mW.
  • #1
cvangheem
1
0
1. Homework Statement
A 200 mW horizontally polarized laser beam passes through a polarizing filter whose axis is 25 degrees from vertical.

What is the power of the laser beam as it emerges from the filter?
P=mW

2. Homework Equations

I0cos2(theta)
I≈E0cos(theta)
I=E0cos2(theta)
I=P/A=(E02)/(cμ0)=(cε0E02)/2

3. The Attempt at a Solution
I have tried numerous ways and I still can't seem to get it
I'm almost positive you must use 65° instead of 25°, and I have ran out of ways for me to do this problem because I don't know how to get my Intensity because we don't know the Area, so I'm sort of stuck
.2= E(incident) cos (65)
E(incident)= .473 ---> wrong






Thanks!
 
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  • #2
Power and intensity are proportional, so just use your first equation (Malus's law).
 

Related to Intensity of Light With a Given Power of Through a Polarizer

1. What is the purpose of using a polarizer in measuring light intensity?

A polarizer is used to control or filter the direction of light waves. By adjusting the orientation of the polarizer, it can either block or allow light waves to pass through, thus affecting the overall intensity of light.

2. How is the intensity of light affected by the power of a polarizer?

The intensity of light is directly proportional to the power of a polarizer. This means that as the power of the polarizer increases, the intensity of light passing through it also increases.

3. Can the intensity of light be measured without a polarizer?

Yes, the intensity of light can be measured without a polarizer. However, using a polarizer allows for more control and precision in measuring the intensity of light.

4. How does the angle of the polarizer affect the intensity of light?

The angle of the polarizer determines the amount of light that can pass through it. When the polarizer is at a 90-degree angle to the light source, it blocks all light waves, resulting in zero intensity. As the angle decreases, more light can pass through, increasing the intensity.

5. Is the intensity of light affected by the color of the light source?

Yes, the color of the light source can affect the intensity of light passing through a polarizer. Different colors have varying wavelengths, which can be filtered differently by the polarizer, resulting in varying intensities.

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