3.4 Refraction, diffraction, and interference

• What happens to waves during reflection?

  They bounce off a surface
• During refraction, the angle of incidence is not equal to the angle of refraction
• Snell's Law is used to predict the angle of refraction.
• Snell's Law describes the relationship between the angles of incidence and refraction.
• Snell's Law is used to predict the angle of refraction
• Snell's Law is expressed mathematically as $n_{1} \sin \theta_{1} =$$n_{2} \sin \theta_{2}$, where $\theta_{1}$ is the angle of incidence
• Refraction is used in glasses to correct vision
• The definition of reflection is the bouncing of waves off a surface
• The wave speed decreases when a wave enters a medium with a higher refractive index.


  True
• Reflection occurs at the boundary of a single medium
• Diffraction occurs when a wave encounters an obstacle or passes through an opening comparable in size to its wavelength.


  True
• Why do low-frequency radio waves diffract around obstacles more than high-frequency light waves?

  Longer wavelength
• Diffraction occurs when waves pass from one medium to another.

  False
• Match the wave phenomenon with its cause:

  Refraction ↔️ Change in wave speed

  Reflection ↔️ No change in wave speed
• When waves undergo refraction, the wave speed is reduced in the new medium
• In reflection, the wave speed changes.

  False
• The wave speed decreases when it enters a medium with a higher refractive index.

  True
• Refraction is used in glasses to correct vision
• Diffraction occurs when waves encounter an obstacle or pass through an opening.


  True
• Longer wavelengths produce more pronounced diffraction patterns.


  True
• Match the wave behavior with its cause:

  Diffraction ↔️ Wave encounters an obstacle

  Refraction ↔️ Change in wave speed

  Reflection ↔️ Wave reaches a boundary
• Radio waves diffract around hills and buildings due to their longer wavelengths
• Why can microwaves in a microwave oven escape through the small holes in the metal grating?

  Diffraction through small openings
• Match the type of interference with its characteristic:

  Constructive Interference ↔️ Aligned in phase

  Destructive Interference ↔️ Out of phase by an odd multiple of π
• Constructive and destructive interference are two types of wave phenomena.


  True
• What does Young's double-slit experiment demonstrate about light?

  Wave nature of light
• Refraction occurs because the wave speed changes as it enters a new medium.

  True
• Snell's Law relates the angles of incidence and refraction to the refractive indices of the media.

  True
• What happens to the wave speed when light enters a medium with a higher refractive index?

  It reduces
• Refraction occurs when waves pass from one medium to another, whereas reflection occurs at the boundary of a single medium
• Refraction is the bending of waves at a boundary, while reflection is the bouncing of waves off a surface
• What happens to light when it enters water, causing underwater objects to appear closer?

  Refraction
• The larger the wavelength of a wave relative to the obstacle size, the greater the degree of diffraction.


  True
• What happens to the angle of a wave when it undergoes diffraction?

  Complex diffraction pattern
• Longer wavelengths produce more pronounced diffraction patterns than shorter wavelengths.

  True
• Match the example of diffraction with its description:

  Sound waves around corners ↔️ Sound waves bend around obstacles

  Light through small openings ↔️ Light creates bright and dark fringes

  Radio waves around hills ↔️ Radio signals reach non-direct line-of-sight areas
• Sound waves bend around corners due to diffraction
• The phase difference between waves determines whether they align constructively or destructively
• Destructive interference occurs when waves are out of phase by an odd multiple of π
• Steps of Young's Double Slit Experiment:

  1️⃣ Coherent light is split by two parallel slits

  2️⃣ Light waves from slits interfere

  3️⃣ Constructive and destructive interference creates fringes

  4️⃣ Fringe spacing depends on wavelength, slit separation, and distance