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SCIENCE · INVESTIGATE AND EXPLAIN

Apply each polarizer to the light reaching it

Polarization describes the direction of a transverse wave field. An ideal first linear polarizer transmits half the intensity of unpolarized input. Once the light is linearly polarized, a second ideal filter transmits a fraction cos²θ, where θ is the angle between its axis and the incoming polarization. That angle must be updated after each filter rather than repeatedly measured from the original source.

Learning outcome: Compare θ=0°,45°,90° with β=90°. Retain each intermediate intensity and its relative projection angle. Then place infrared and ultraviolet on opposite sides of visible light and predict which has the larger vacuum wavelength without assigning a health threshold.

Starting recap

Use normal-based angles, signed conjugate distances and explicit optical-path/reflection phases. Separate geometric direction, amplitude and energy; preserve focal and critical boundaries.

All lessons are open directly. Your saved experiments remain when you leave and return.

Try

At θ=45° and β=90°, the successive intensities are5,2.5,1.25 W/m². Directly crossed first and third filters would give0. At θ=90°, the second filter already removes all ideal input and no third orientation restores it. Violet has higher frequency and shorter vacuum wavelength than red under the stated ordering.

Open the experiment

Predict

Why can a45° intermediate polarizer allow light through crossed first and final axes?

Experiment

Compare θ=0°,45°,90° with β=90°. Retain each intermediate intensity and its relative projection angle. Then place infrared and ultraviolet on opposite sides of visible light and predict which has the larger vacuum wavelength without assigning a health threshold.

Track each projection relative to the preceding polarizer

Worked teaching model · synthetic values · Unpolarized input intensity10 W/m². First ideal polarizer passes half; second and third ideal axes are specified relative to first. Malus projections use angle differences, not all absolute angles. No optical exposure, real filter loss or biological vision model.

Reset keeps your prediction, captures and practice history.

Intermediate-axis dependence with fixed final axis

final intensity (W/m²)second axis from first (degrees)0901.250

Unlike graph quantities rescale independently; read units and values, not screen angles. 1: three-polarizer chain (solid). Joined curves show the supplied model, not additional observations.

Equivalent numerical coordinates for Intermediate-axis dependence with fixed final axis

three-polarizer chain

second axis from first (degrees)final intensity (W/m²)
00
1.1250.00192667
2.250.00769479
3.3750.0172688
4.50.0305897
5.6250.0475753
6.750.0681209
7.8750.0920999
90.119364
10.1250.149746
11.250.183058
12.3750.219095
13.50.257634
14.6250.298438
15.750.341256
16.8750.385823
180.431864
19.1250.479097
20.250.527228
21.3750.575963
22.50.625
23.6250.674037
24.750.722772
25.8750.770903
270.818136
28.1250.864177
29.250.908744
30.3750.951562
31.50.992366
32.6251.03091
33.751.06694
34.8751.10025
361.13064
37.1251.1579
38.251.18188
39.3751.20242
40.51.21941
41.6251.23273
42.751.24231
43.8751.24807
451.25
46.1251.24807
47.251.24231
48.3751.23273
49.51.21941
50.6251.20242
51.751.18188
52.8751.1579
541.13064
55.1251.10025
56.251.06694
57.3751.03091
58.50.992366
59.6250.951562
60.750.908744
61.8750.864177
630.818136
64.1250.770903
65.250.722772
66.3750.674037
67.50.625
68.6250.575963
69.750.527228
70.8750.479097
720.431864
73.1250.385823
74.250.341256
75.3750.298438
76.50.257634
77.6250.219095
78.750.183058
79.8750.149746
810.119364
82.1250.0920999
83.250.0681209
84.3750.0475753
85.50.0305897
86.6250.0172688
87.750.00769479
88.8750.00192667
900

At most 82 representative computed coordinates including endpoints; the plotted curve can use a finer grid. A table of a revealed generator is not independent measurement evidence.

Calculated quantities under the declared measurement model
QuantityValueUnit
After first ideal polarizer5W/m²
After second polarizer2.5W/m²
After third polarizer1.25W/m²
Without the intermediate second polarizer0W/m²
Total rejected or absorbed intensity8.75W/m²

Each filter projects the polarization incident on it; inserted projection can enable nonzero final transmission without creating energy.

Unpolarized intensity halves at the first ideal linear polarizer. The next projection uses theta and the final projection beta−theta. At crossed first/last axes beta90, an intermediate theta45 gives1.25 W/m² while directly crossed filters give zero. Every stage transmits no more than its own input. Polarization is evidence of transverse electromagnetic waves; an ideal linear-polarizer model is not a description of ordinary longitudinal sound in a fluid.

Predict before inspecting the values. Save contrasting records with assumptions and one alternative explanation. This virtual display does not certify practical measurement technique.

Each filter projects the polarization incident on it; inserted projection can enable nonzero final transmission without creating energy.

Unpolarized intensity halves at the first ideal linear polarizer. The next projection uses theta and the final projection beta−theta. At crossed first/last axes beta90, an intermediate theta45 gives1.25 W/m² while directly crossed filters give zero. Every stage transmits no more than its own input. Polarization is evidence of transverse electromagnetic waves; an ideal linear-polarizer model is not a description of ordinary longitudinal sound in a fluid.

Captures preserve recipes and replay their calculated results. They are synthetic model evidence, not physical measurements.

Understand

Define the optical model

Polarization describes the direction of a transverse wave field. An ideal first linear polarizer transmits half the intensity of unpolarized input. Once the light is linearly polarized, a second ideal filter transmits a fraction cos²θ, where θ is the angle between its axis and the incoming polarization. That angle must be updated after each filter rather than repeatedly measured from the original source.

Build the signed account

The input here is10 W/m², so the first filter leaves5. The second axis is at θ relative to the first; the third is at β relative to the first. Final intensity is5 cos²θ cos²(β−θ). With first and final axes crossed, an intermediate45° axis permits1.25 W/m² even though removing it leaves zero. Every filter still transmits no more than its own input; projection and absorption explain the result without creating energy.

Test the limits and evidence

Electromagnetic waves are transverse and need no material medium in vacuum, unlike ordinary longitudinal sound in a fluid. Increasing vacuum frequency runs through radio, microwave, infrared, visible, ultraviolet, X-ray and gamma-ray regions; within visible light it runs from red through orange, yellow, green and blue to violet. Frequency and vacuum wavelength are inversely related through c=fλ. Spectrum names do not by themselves set a safe exposure or a detailed biological effect, and this model supplies no such guidance.

Worked original case

At θ=45° and β=90°, the successive intensities are5,2.5,1.25 W/m². Directly crossed first and third filters would give0. At θ=90°, the second filter already removes all ideal input and no third orientation restores it. Violet has higher frequency and shorter vacuum wavelength than red under the stated ordering.

Predict and investigate

Compare θ=0°,45°,90° with β=90°. Retain each intermediate intensity and its relative projection angle. Then place infrared and ultraviolet on opposite sides of visible light and predict which has the larger vacuum wavelength without assigning a health threshold.

Changed-case practice

Try the changed case before feedback

For unpolarized input8 W/m² followed by axes0°,45°,90°, find final intensity in W/m².

This practice is public and unsaved. A matching number does not verify understanding. Retain your explanation, assumptions and changed-case evidence in the separate course workspace.

Sources and boundaries

Original text and numerical cases checked 30 October 2026 against the primary explanation. All optical activity is virtual: no laser, sunlight viewing, eye exposure, physical lens alignment or device construction is requested. Public feedback is not independent mastery; retain first calculations, critique and changed-case evidence in the separate course workspace.

Apply

Why can a45° intermediate polarizer allow light through crossed first and final axes?

Public practice checks a specific claim. It does not establish independent mastery.

Which independent observation would reject the approximation, sign convention or calibration premise rather than merely refit it?

Continue

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