Physics HL
Physics HL
5
Chapters
329
Notes
Theme A - Space, Time & Motion
Theme A - Space, Time & Motion
Theme B - The Particulate Nature Of Matter
Theme B - The Particulate Nature Of Matter
Theme C - Wave Behaviour
Theme C - Wave Behaviour
Theme D - Fields
Theme D - Fields
Theme E - Nuclear & Quantum Physics
Theme E - Nuclear & Quantum Physics
IB Resources
Theme C - Wave Behaviour
Physics HL
Physics HL

Theme C - Wave Behaviour

Understanding Single-Slit Diffraction: A Deep Dive

Word Count Emoji
630 words
Reading Time Emoji
4 mins read
Updated at Emoji
Last edited onย 5th Nov 2024

Table of content

Hey, physics enthusiasts! ๐Ÿš€๐ŸŒŒ Let's dive into the fascinating world of single-slit diffraction, an exciting phenomenon of wave optics! ๐ŸŒˆ๐Ÿ”

Diffraction & interference

Introduction: When plane waves hit a single slit of width b, they are divided into many individual wavelets, which then expand as circular waves. This phenomenon is called diffraction.

  • Diffraction Minima: The positions of the diffraction minima (dark fringes) can be modeled using destructive interference and superposition.
  • Huygens' Principle: Every point on a wavefront acts as a source of secondary wavelets.

Modelling the first diffraction minimum ๐ŸŒ‘

  • Point Sources: The first diffraction minimum is modeled by considering a point source A at the edge of the slit and another point source halfway down the slit at B.
  • Destructive Interference: Every point source in the top half of the slit has a counterpart in the bottom half. They interfere destructively, canceling out to give zero intensity at the first diffraction minimum.
  • Phase Difference: Each pair of wavelets arrives exactly π out of phase. For this, the light from the bottom source must travel half a wavelength (๐œ†/2) more than the light from the upper source. This is the path difference between the two waves.
  • Geometry of Diffraction: The extra distance traveled by the bottom source is equal to b/2 sin θ1. By equating this with ๐œ†/2, we get sin θ1 = ๐œ†/b and for small angles, θ1 ≈ ๐œ†/b. This is the angular position of the first diffraction minimum.

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IB Resources
Theme C - Wave Behaviour
Physics HL
Physics HL

Theme C - Wave Behaviour

Understanding Single-Slit Diffraction: A Deep Dive

Word Count Emoji
630 words
Reading Time Emoji
4 mins read
Updated at Emoji
Last edited onย 5th Nov 2024

Table of content

Hey, physics enthusiasts! ๐Ÿš€๐ŸŒŒ Let's dive into the fascinating world of single-slit diffraction, an exciting phenomenon of wave optics! ๐ŸŒˆ๐Ÿ”

Diffraction & interference

Introduction: When plane waves hit a single slit of width b, they are divided into many individual wavelets, which then expand as circular waves. This phenomenon is called diffraction.

  • Diffraction Minima: The positions of the diffraction minima (dark fringes) can be modeled using destructive interference and superposition.
  • Huygens' Principle: Every point on a wavefront acts as a source of secondary wavelets.

Modelling the first diffraction minimum ๐ŸŒ‘

  • Point Sources: The first diffraction minimum is modeled by considering a point source A at the edge of the slit and another point source halfway down the slit at B.
  • Destructive Interference: Every point source in the top half of the slit has a counterpart in the bottom half. They interfere destructively, canceling out to give zero intensity at the first diffraction minimum.
  • Phase Difference: Each pair of wavelets arrives exactly π out of phase. For this, the light from the bottom source must travel half a wavelength (๐œ†/2) more than the light from the upper source. This is the path difference between the two waves.
  • Geometry of Diffraction: The extra distance traveled by the bottom source is equal to b/2 sin θ1. By equating this with ๐œ†/2, we get sin θ1 = ๐œ†/b and for small angles, θ1 ≈ ๐œ†/b. This is the angular position of the first diffraction minimum.

Unlock the Full Content! File Is Locked Emoji

Dive deeper and gain exclusive access to premium files of Physics HL. Subscribe now and get closer to that 45 ๐ŸŒŸ

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