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Question #43573
The Question
Two coherent monochromatic electromagnetic waves, Wave 1 and Wave 2, propagate in a vacuum along the direction. Their electric field vectors are given by: where is a constant amplitude in , is the wave number in , and is the angular frequency in . The time-averaged intensity of Wave 1 alone is (in ). The two waves are superposed, and the resultant wave is incident normally on an ideal linear polarizer. The transmission axis of the polarizer lies in the -plane and makes an angle of with the positive -axis. What is the time-averaged intensity of the transmitted wave?
Options
- A.
- B.
- C.
- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Intuition_Breaker
Train your brain to resist "obvious" answers that are designed to deceive your intuition.
Concepts Behind This Question
Superposition Principle|Transverse Nature of EM Waves|Photon Polarization and Selection|Vector Cross-Products
Why This Question Is Tricky
Common Mistakes
Students often fall into the trap of treating the two orthogonal waves as independent, incoherent sources, incorrectly applying Malus's Law to their intensities separately: .
This scalar addition completely ignores the superposition principle for coherent waves.
Because the waves are coherent, their electric field vectors must be superposed first, creating an elliptically polarized state.
Projecting this resultant vector onto the analyzer's axis reveals an interference term that dictates the true transmitted intensity.
This question tests the critical transition from classical scalar wave addition to vector state evolution in polarization.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Wave Optics - Class 12 |
| Concept | Superposition Principle |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |