How Does Light Intensity Change Through Three Stacked Polarizing Films?

  • Thread starter Thread starter chaosprimer
  • Start date Start date
AI Thread Summary
When three perfect polarizing films are stacked with each oriented at +45 degrees relative to the previous one, the intensity of light passing through can be calculated using the Law of Malus. The initial light intensity of 1 watt will be reduced by the first polarizer to 0.5 watts, as it allows half of the light to pass through at a 0-degree angle. The second polarizer, oriented at 45 degrees, further reduces the intensity to approximately 0.25 watts. Finally, the third polarizer, oriented at 90 degrees, allows another reduction, resulting in an overall transmitted intensity of about 0.125 watts. Understanding these principles is crucial for analyzing light behavior through multiple polarizers.
chaosprimer
Messages
1
Reaction score
0
If you have 3 perfect polarizing films and you place them on top of the other, with each successive film oriented +45 degrees from the one before it (first and last oriented perpendicular to each other and middle polarizer at 45 degrees between them). If one shines a light on this polarizer stack with an intensity of 1 watt, what is the intensity of the light on the other side of the three polarizer stack?

Now when I tried to figure this out I assume that the light is collimated and that the films are perfect polarizer. But I got stuck on the actually equation... Anyone out there knows how to solve this?
 
Physics news on Phys.org
Perhaps the Law of Malus applies.

For each polarizer - Itrans = Io cos2\theta, where \theta is the angle of between axis of polarizer and some reference.

The question is what is the transmission of light through the first polarizer.

Edit: See http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/polcross.html

for discussion of crossed polarizers and Law of Malus.
 
Last edited:

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Discover the Effects of Rotating Polarizing Films | Explained with Examples
Replies
10
Views
2K
Effect of Rotating Polarizing Films
Replies
8
Views
3K
Intensity of light through two polarizers
Replies
3
Views
3K
Intensity of light passing through 3 polarizers
Replies
3
Views
6K
How can light be partially polarized?
Replies
6
Views
2K
The maximum intensity for light transmitted through a thin film
Replies
2
Views
3K
2 Polarizers attenuating a light beam
Replies
11
Views
2K
Why Does Unpolarized Light Lose Half Its Intensity Through a Polaroid?
Replies
4
Views
2K
Intensity after different polarizers
Replies
7
Views
9K
I What happens when circular polarization meets a diagonal polarizer?
Replies
20
Views
3K

Hot Threads

Recent Insights

Back
Top