3.4 Refraction, diffraction, and interference

• The refractive index of a material quantifies how much the speed of light is reduced in that medium compared to its speed in vacuum
• When light travels from air to glass at an angle of incidence of 30 degrees, what happens to the angle of refraction?

  Decreases
• Total internal reflection occurs when light travels from a denser medium to a less dense medium and the angle of incidence exceeds the critical angle
• The critical angle is the angle of incidence at which the angle of refraction is 90 degrees.
• The angle of incidence must be greater than the critical angle for total internal reflection to occur.


  True
• The critical angle for light traveling from glass to air is approximately 41.8^\circ</latex>.


  True
• The diffraction angle $\theta$ can be approximated using the formula $\sin(\theta) \approx \frac{\lambda}{d}$.wavelength.
• When light moves from air to water, it bends towards the normal.

  True
• In Snell's Law, $\theta_{1}$ represents the angle of incidence.
• The critical angle for light traveling from glass to air is approximately $41.8^\circ$.


  True
• Diffraction is most noticeable when the wavelength of the wave is comparable to the size of the obstacle or aperture.


  True
• What happens to waves when their wavelength is much larger than the aperture size?

  Almost complete spreading
• What does $\lambda$ represent in the diffraction angle formula?


  Wavelength of light
• What does $d$ represent in the single-slit minima formula?


  Width of the slit
• Match the feature with the type of diffraction:

  Fringe Spacing ↔️ Non-uniform for single-slit, uniform for double-slit

  Intensity Distribution ↔️ Central bright fringe strongest in single-slit

  Governing Formula ↔️ $d \sin \theta =$$m \lambda$ for single-slit
• Destructive interference occurs when the phase difference is $(2n + 1)\pi$, resulting in zero or weaker amplitude.
• Constructive interference occurs when the phase difference is an integer multiple of 2\pi
• In Young's Double Slit Experiment, bright fringes form where the path difference is n\lambda
• Snell's Law relates the angles of incidence and refraction using the refractive indices
• When light enters a denser medium, it bends towards the normal.


  True
• What is the critical angle defined as?

  Angle of 90° refraction
• If the angle of incidence exceeds the critical angle, all light is reflected back into the denser medium.


  True
• What is the approximate formula for the diffraction angle $\theta$?


  $\sin(\theta) \approx \frac{\lambda}{d}$
• The single-slit minima are described by the formula $d \sin \theta =$$m \lambda$.


  True
• What type of fringes are produced in a double-slit diffraction pattern?

  Bright and dark
• What does $d$ represent in the double-slit formula?


  Distance between slits
• Which fringe in a single-slit diffraction pattern has the highest intensity?

  Central bright fringe
• What does $m$ represent in the single-slit formula?


  Order of the minimum
• Snell's Law describes the relationship between the angles of incidence and refraction.


  True
• Steps to apply Snell's Law

  1️⃣ Identify the refractive indices of the two media

  2️⃣ Determine the angle of incidence

  3️⃣ Use the formula to calculate the angle of refraction
• The critical angle is the angle of incidence at which the angle of refraction is 90 degrees.


  True
• The critical angle is calculated using the formula \theta_c = \sin^{-1}\left(\frac{n_2}{n_1}\right)</latex>.

  True
• Conditions for total internal reflection

  1️⃣ Light travels from a denser to a less dense medium.

  2️⃣ The angle of incidence exceeds the critical angle.
• Diffraction is the spreading or bending of waves as they pass around obstacles or through small openings.
• Diffraction is most noticeable when the wavelength of the wave is comparable to the size of the obstacle or aperture.


  True
• The refractive index of a material quantifies how much the speed of light is reduced compared to its speed in vacuum.
• When light travels from air to glass at an incidence angle of 30^\circ</latex>, the angle of refraction is approximately $19.5^\circ$.


  True
• Diffraction is most noticeable when the wavelength of the wave is comparable to the size of the obstacle or aperture.
• When the wavelength is comparable to the aperture size, significant bending occurs.
• Waves with a wavelength much smaller than the aperture size undergo minimal bending.


  True