Boundary Behavior of Waves and Polarization - AP Physics 2

1. Define linear polarization.

   Vibration occurs in a single direction perpendicular to wave travel. Electric field vector oscillates in one plane only.

2. Identify one factor affecting wave refraction.

   The change in wave speed affects refraction. Speed changes cause direction changes at boundaries.

3. What is the phase difference for destructive interference?

   Phase difference is odd multiples of $\text{π}$. Waves are out of phase, creating maximum cancellation.

4. What is the effect of a denser medium on wave amplitude?

   Amplitude generally decreases in a denser medium. Denser media typically absorb more energy from waves.

5. Identify the condition for wave reflection at a boundary.

   Reflection occurs when wave impedance changes. Impedance mismatch causes partial reflection at interfaces.

6. What is the phase difference for constructive interference?

   Phase difference is $0$ or multiples of $2\text{π}$. Waves are in phase, creating maximum reinforcement.

7. What is an antinode?

   A point of maximum amplitude in a standing wave. Formed when incident and reflected waves interfere constructively.

8. What is the purpose of using polarizing filters in photography?

   To reduce glare and enhance contrast. Removes unwanted reflections and improves image clarity.

9. What is circular polarization?

   Wave's electric field rotates in a circle around the direction of travel. Electric field vector traces circular path perpendicular to propagation.

10. State Snell's law.

    $n_1 \times \text{sin}(\theta_1) = n_2 \times \text{sin}(\theta_2)$. Relates incident and refracted angles through refractive indices.

11. What is the outcome of wave interference?

    Interference results in either increased or decreased wave amplitude. Depends on phase relationship between overlapping waves.

12. What happens to wave speed at a boundary?

    Wave speed changes depending on the medium. Different media have different wave propagation speeds.

13. What occurs to wave frequency when crossing a boundary?

    Wave frequency remains unchanged. Frequency is an intrinsic property that doesn't change across boundaries.

14. Define wave reflection.

    Wave reflection is when a wave bounces back after hitting a boundary. Energy cannot pass through the boundary, so it returns to the original medium.

15. What is wave diffraction?

    Diffraction is the bending of waves around obstacles. Wave spreading occurs when encountering edges or apertures.

16. What happens to light intensity after passing through a polarizer?

    Intensity is reduced by half. Unpolarized light becomes 50% intensity after polarization.

17. What is a node?

    A point of zero amplitude in a standing wave. Formed when incident and reflected waves interfere destructively.

18. What happens to a wave's speed when it enters a denser medium?

    The wave's speed decreases. Denser media have higher refractive indices, slowing wave propagation.

19. What is polarization of light?

    Polarization is restricting the vibration of light waves to one plane. Only transverse waves can be polarized, not longitudinal waves.

20. What is the formula for Brewster's angle?

    $\tan(\theta_B) = \frac{n_2}{n_1}$. Derived from the condition that reflected and refracted rays are perpendicular.

21. Define isotropic medium.

    A medium with uniform properties in all directions. Wave properties are identical in all spatial directions.

22. Identify the condition for maximum diffraction.

    Occurs when the aperture size is comparable to the wavelength. Significant bending occurs when $\lambda \approx$ aperture size.

23. Define destructive interference.

    When waves overlap to produce a smaller amplitude. Wave crests align with troughs, creating cancellation.

24. What is the difference between longitudinal and transverse waves?

    Longitudinal waves oscillate parallel; transverse waves oscillate perpendicular. Describes the relationship between oscillation and propagation directions.

25. What is the effect of polarization on glare reduction?

    Polarization reduces glare. Eliminates horizontally polarized reflected light from surfaces.

26. What occurs to light waves at Brewster's angle?

    Reflected light is completely polarized. At this specific angle, reflected light has maximum polarization.

27. Identify the condition for total internal reflection.

    Occurs when the angle of incidence exceeds the critical angle. When $\theta_i > \theta_c$, all energy reflects and none transmits.

28. What is the principle of superposition for waves?

    The total displacement is the sum of individual displacements. Multiple waves combine by adding their displacements at each point.

29. What happens to wave amplitude during constructive interference?

    The amplitude increases. Wave peaks align to create larger displacement.

30. What is the critical angle formula?

    $\theta_c = \text{sin}^{-1}(\frac{n_2}{n_1})$. Critical angle depends on the ratio of refractive indices.

31. How does wave frequency affect diffraction?

    Higher frequency reduces diffraction. Shorter wavelengths diffract less around obstacles.

32. Define constructive interference.

    When waves overlap to produce a larger amplitude. Wave crests align with crests, creating reinforcement.

33. What is the law of reflection for waves?

    Angle of incidence equals angle of reflection. This is a fundamental principle governing all types of wave reflection.

34. What happens to wave amplitude during destructive interference?

    The amplitude decreases. Wave peaks and troughs align to cancel displacement.

35. Describe Brewster's angle.

    The angle where reflected light is completely polarized. Occurs when the reflected ray is perpendicular to the refracted ray.

36. What is the relationship between wave speed and medium density?

    Wave speed decreases with increased medium density. Inverse relationship between medium density and wave speed.

37. What is the effect of polarization on light intensity?

    Polarization reduces the light intensity. Filtering light waves removes some energy from the beam.

38. What is wave transmission?

    Transmission is when a wave passes through a boundary into a new medium. Part of wave energy continues into the second medium.

39. Define wave refraction.

    Refraction is the change in wave direction at a boundary. Speed changes cause waves to bend when entering new media.

40. What is meant by wave impedance?

    Wave impedance is the resistance a medium offers to wave motion. Characterized by the product of density and wave speed.

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