14.4 Diffraction and Polarization

• What is diffraction?

  Bending of waves
• Each point on the wavefront acts as a new wave source
• Fraunhofer diffraction involves plane wavefronts.

  True
• Fresnel diffraction produces a diffraction pattern that is simple and predictable.

  False
• In Fresnel diffraction, the observation occurs in the near field.
• What type of wave is light?

  Electromagnetic
• What type of wavefronts are involved in Fraunhofer diffraction?

  Plane
• What type of wave is light?

  Electromagnetic
• What happens to diffraction when the frequency of light increases?

  Decreases
• What fundamental phenomenon does Huygens' principle explain?

  Diffraction
• What are the two main types of diffraction?

  Fraunhofer and Fresnel
• Under what condition does Fresnel diffraction occur?

  Near field
• Order the complexity of diffraction analysis from simplest to most complex:

  1️⃣ Fraunhofer Diffraction

  2️⃣ Fresnel Diffraction
• Fraunhofer diffraction occurs when the observation distance is much greater than the size of the obstacle
• Fresnel diffraction is observed in the near field
• Red light has a longer wavelength
• According to Huygens' Principle, each point on a wavefront acts as a source of new spherical waves
• The minima in a single-slit diffraction pattern occur due to constructive interference.

  False
• Minima in Young's double-slit experiment occur when the path difference is an integer multiple of the wavelength.

  False
• Match the type of polarization with its description:

  Linear ↔️ Electric field oscillates in a fixed direction

  Circular ↔️ Electric field rotates in a circular motion

  Elliptical ↔️ Electric field rotates in an elliptical motion
• Order the following steps to describe Fraunhofer diffraction:

  1️⃣ Observation distance is much greater than obstacle size

  2️⃣ Wavefronts are considered plane

  3️⃣ Diffraction pattern is observed in the far field
• In Fresnel diffraction, the wavefronts are curved.


  True
• Match the aspect with the correct type of diffraction:

  Observation Distance ↔️ Much greater than obstacle size for Fraunhofer

  Wavefronts ↔️ Plane for Fraunhofer

  Complexity of Pattern ↔️ Complex and less predictable for Fresnel
• What type of wavefronts are involved in Fraunhofer diffraction?

  Plane
• According to Huygens' principle, each point on a wavefront acts as a source of new spherical waves
• In single-slit diffraction, minima occur where $\sin \theta =$$m \frac{\lambda}{w}$, where \( m = \pm 1, \pm 2, \dots \), and \( w \) is the slit width
• In Young's double-slit experiment, maxima occur where $d \sin \theta =$$m \lambda$, where \( d \) is the slit separation
• What is the approximate angle to the first maximum in Young's double-slit experiment for slits separated by 0.1 mm and red light with a wavelength of 650 nm?

  0.37 degrees
• What does \( \lambda \) represent in the formula for destructive interference?

  Wavelength
• Match the type of diffraction with its observation distance:

  Fraunhofer Diffraction ↔️ Large

  Fresnel Diffraction ↔️ Comparable to obstacle size
• Fresnel diffraction occurs when the wavefronts are curved
• What type of wavefronts are involved in Fraunhofer diffraction?

  Plane
• Match the type of diffraction with its example:

  Fraunhofer Diffraction ↔️ Light through a narrow slit

  Fresnel Diffraction ↔️ Water waves around a rock
• Higher frequency light waves have less diffraction
• Fresnel diffraction involves curved wavefronts in the near field.


  True
• Which color of light diffracts more when passing through the same opening, red or blue?

  Red
• According to Huygens' principle, each point on a wavefront acts as a source of new spherical waves
• Diffraction is the bending of waves around obstacles or through openings
• In Fraunhofer diffraction, the wavefronts are considered plane.


  True
• Match the diffraction type with its characteristic:

  Fraunhofer Diffraction ↔️ Plane wavefronts

  Fresnel Diffraction ↔️ Curved wavefronts

  Observation Distance in Fraunhofer ↔️ Much greater than obstacle

  Observation Distance in Fresnel ↔️ Comparable to obstacle