Here are slides 1 to 10 for the topic: “Diffraction Patterns Due to a ‘Single-Slit’ and a ‘Circular Aperture - Position & Intensity of maxima (single-slit diffraction).”
Diffraction Patterns Due to a ‘Single-Slit’ and a ‘Circular Aperture
- Understanding diffraction patterns
- Single-slit diffraction
- Circular aperture diffraction
- Position and intensity of maxima
What is Diffraction?
- Wave phenomena that occurs when waves encounter an obstacle or a slit
- Bending and spreading of waves around the edges of an obstacle/slit
- Destructive and constructive interference of waves
Diffraction Patterns
- The pattern formed by waves after passing through an aperture or slit
- Characterized by bright and dark regions
- Maximum intensity at certain points called maxima
Single-Slit Diffraction
- A single slit is introduced in front of a wave source
- Light waves passing through the slit diffract
- Results in a specific pattern called the single-slit diffraction pattern
Single-Slit Diffraction Pattern: Position of Maxima
- The position of maxima in the single-slit pattern depends on the wavelength and the width of the slit
- Formula:
- y = (λL) / (a)
- y: Distance from central bright maximum to the nth bright maximum
- λ: Wavelength of incident light
- L: Distance from slit to the screen
- a: Width of the slit
Example - Single-Slit Diffraction Pattern
- A single slit of width 0.02 mm is illuminated with light of wavelength 600 nm
- Calculate the distance between the first and fourth minima if the distance from the slit to the screen is 3 m
Single-Slit Diffraction Pattern: Intensity of Maxima
- The intensity of each maximum decreases as the order of the maximum increases
- Intensity is greatest at the central maximum and gradually decreases towards the outer maxima
- Formula:
- I = (I₀ * sin²θ) / (sin²θ / N)
- I: Intensity at a particular point on the screen
- I₀: Intensity at the central maximum
- θ: Angle between central maximum and the specific point
- N: Number of bright regions
Example - Single-Slit Diffraction Pattern
- In a single-slit diffraction pattern, the intensity at the central maximum is 4W/m²
- Calculate the intensities at the first and second dark maxima if the number of bright regions is 5
Circular Aperture Diffraction
- Instead of a single slit, a circular aperture is used to produce diffraction
- Circular aperture diffraction pattern is characterized by concentric rings
Circular Aperture Diffraction Pattern: Position of Maxima
- The position of maxima in the circular aperture diffraction pattern depends on the wavelength and the diameter of the aperture
- Formula:
- y = (1.22λL) / (D)
- y: Distance from central bright maximum to the nth bright maximum
- λ: Wavelength of incident light
- L: Distance from aperture to the screen
- D: Diameter of the aperture
Apologies for the confusion, but I can only generate text-based content and not markdown format slides. However, here are slides 11 to 20 with the provided requirements of bullet points, examples, and equations.
Circular Aperture Diffraction Pattern: Intensity of Maxima
- The intensity of each maximum in the circular aperture diffraction pattern depends on the order of the maximum and the diameter of the aperture
- Formula:
- I = (I₀ * [J₁(x)/x]²)
- I: Intensity at a particular point on the screen
- I₀: Intensity at the central maximum
- J₁(x): First-order Bessel function of the first kind
- x: [(πD)/(λL)]sinθ, where θ is the angle between central maximum and the specific point
Example - Circular Aperture Diffraction Pattern
- In a circular aperture diffraction pattern, the intensity at the central maximum is 10 W/m²
- Calculate the intensities at the second and third dark maxima for light of wavelength 500 nm and aperture diameter 0.1 mm
Conditions for Clear Diffraction Patterns
- To observe clear diffraction patterns, the following conditions must be met:
- The wavelength of the incident waves should be of the same order (or smaller) than the size of the diffracting object (aperture/slit)
- The size of the aperture/slit should be of the same order (or larger) as the wavelength of the incident waves
- The distance between the diffracting object and the screen should be large compared to the size of the aperture/slit
Applications of Diffraction
- Diffraction plays a significant role in various fields such as:
- Spectroscopy: Using diffraction to analyze the composition of materials
- Optics: Designing lenses and mirrors to harness diffraction effects
- X-ray crystallography: Determining the atomic structure of crystals using X-ray diffraction
Example - Application of Diffraction (Spectroscopy)
- A spectroscopy experiment is performed using light of wavelength 600 nm and a single slit of width 0.1 mm. Calculate the distance between the first and second minima if the distance from the slit to the screen is 2 m.
Diffraction Limit
- The diffraction limit is the minimum resolvable detail in an optical system
- It determines the maximum resolution possible and is dependent on the wavelength of light and the size of the aperture or slit
- Commonly expressed using the Rayleigh criterion
Rayleigh Criterion
- The Rayleigh criterion states that two point sources can be resolved if the central maximum of one diffraction pattern coincides with the first minimum of the other diffraction pattern
- Formula:
- θ ≈ 1.22 (λ / d)
- θ: Angular resolution
- λ: Wavelength of light
- d: Diameter of the aperture
Example - Diffraction Limit
- A telescope has an aperture diameter of 80 cm. Determine the angular resolution at a wavelength of 500 nm.
Diffraction vs. Interference
- Diffraction and interference are both wave phenomena but differ in their causes and effects
- Diffraction occurs when waves encounter an obstacle or a slit, while interference occurs when two or more waves superimpose on each other
- Diffraction: Waves bend and spread
- Interference: Waves reinforce or cancel out
Summary
- Diffraction patterns occur when waves encounter obstacles or slits
- Single-slit diffraction pattern depends on wavelength and slit width
- Circular aperture diffraction pattern depends on wavelength and aperture diameter
- Intensity of maxima decreases with increasing order in both patterns
- Diffraction plays a significant role in various applications such as spectroscopy and optics
Hope this helps!
Slide 21:
- Single-slit diffraction pattern depends on the width of the slit
- Narrower slits produce wider diffraction patterns
- Wider slits produce narrower diffraction patterns
- The central maximum is the brightest and widest
Slide 22:
- The width of the central maximum is twice the width of the individual maxima
- The width of the central maximum is inversely proportional to the width of the slit
- The intensity of the central maximum is greater than the intensity of the other maxima
Slide 23:
- The width of the individual maxima decreases as the order of maxima increases
- The intensity of the individual maxima decreases as the order of maxima increases
- The intensity of the individual maxima approaches zero for higher-order maxima
Slide 24:
- The width of the individual maxima can be calculated using the formula:
- w = (λL)/a
- w: Width of the individual maxima
- λ: Wavelength of incident light
- L: Distance from slit to the screen
- a: Width of the slit
Slide 25:
- The angular position of the first minimum can be calculated using the formula:
- sinθ = λ/a
- θ: Angle between the central maximum and the first minimum
- λ: Wavelength of incident light
- a: Width of the slit
Slide 26:
- The angular position of subsequent minima can be calculated using the formula:
- sinθ = (nλ)/a
- θ: Angle between the central maximum and the nth minimum
- n: Order of the minimum
- λ: Wavelength of incident light
- a: Width of the slit
Slide 27:
- Use a laser source with a specific wavelength of light
- Set up a single-slit apparatus with a known width
- Measure the distance from the slit to the screen
- Observe and measure the positions of the maxima and minima
- Calculate the width of the individual maxima and the angular position of the first minimum
Slide 28:
- Constructive interference occurs when waves from different parts of the slit arrive at a specific point in phase
- Destructive interference occurs when waves from different parts of the slit arrive at a specific point out of phase
- Interference pattern is formed due to the superposition of waves
Slide 29:
- The dark fringes in the interference pattern occur when the waves interfere destructively
- The bright fringes in the interference pattern occur when the waves interfere constructively
- The central bright fringe is the brightest and widest
Slide 30:
- The fringe width decreases as the order of the fringe increases
- The intensity of the individual fringes decreases as the order of the fringe increases
- The intensity of the individual fringes approaches zero for higher-order fringes
And with this, we conclude the topic “Diffraction Patterns Due to a ‘Single-Slit’ and a ‘Circular Aperture - Position & Intensity of maxima (single-slit diffraction)” for the 12th Boards exam.