Grade10ADVTerm320242025 - SaifMohamed

Lenses

Objectives

• Distinguish between convex and concave lenses.
• Draw the image given by a convex and concave lens and list its characteristics.
• Relate the focal length to the position of the object and that of the image.
• Explain how to correct long-sightedness and short-sightedness using lenses.

Convex and Concave Lenses

• Difference in shapes between convex and concave lenses.
• Phenomenon of light occurring in these lenses.
• Differentiating between convex and concave lenses if shape is not apparent.
• Objective: Distinguish between convex and concave lenses.
• Success Criteria: List the differences between convex and concave lenses.

Convex Lenses

• Convex lenses have thin edges.
• A parallel beam converges into 1 point called the focal point of the lens.
• The distance between the center of the lens and the focus (focal point) is called focal length.
• The focal length is positive.
• Objective: Distinguish between convex and concave lenses.
• Success Criteria: List the characteristics of a convex lens.

Convex Lenses - Particular Rays

• Objective: Distinguish between convex and concave lenses.
• Success Criteria: Draw particular rays passing through convex lens

Convex Lenses - Particular Rays

• A ray parallel to the axis continues passing through the focus.
• A ray passing through the optical center continues without deviation.
• A ray passing through the focus continues parallel to the axis.
• Objective: Distinguish between convex and concave lenses.
• Success Criteria: Draw particular rays passing through convex lens

Convex Lenses - Formation of images

• Objective: Draw the image given by a convex and concave lens and list its characteristics.
• Success Criteria: Draw the image of an object given by a convex lens.

Characteristics of an image

• The image is A'B':
  • Nature: real
  • Direction: Inverted
  • Size: A'B' > AB
  • Position: OB' > OB
• Objective: Draw the image given by a convex and concave lens and list its characteristics.
• Success Criteria: List the characteristics of an image.

Characteristics of an image

• The image is A'B':
  • Nature: Virtual
  • Direction: Upright
  • Size: A'B' > AB
  • Position: OB' > OB
• NOTE: this is the case of a magnifier
• Objective: Draw the image given by a convex and concave lens and list its characteristics.
• Success Criteria: List the characteristics of an image.
• Note:
  • The image is real when we get it on the right side; in this case, it will be collected on a SCREEN.
  • The image is virtual when you see it inside the lens.

Concave Lenses

• Concave lenses have thick edges.
• A parallel beam diverges when passing through a concave lens.
• The distance between the center of the lens and the focus (focal point) is called focal length.
• The focal length is negative.
• Objective: Distinguish between convex and concave lenses.
• Success Criteria: List the characteristics of a concave lens.

Concave Lenses - Particular Rays

• Objective: Distinguish between convex and concave lenses.
• Success Criteria: Draw particular rays passing through concave lens

Concave Lenses - Particular Rays

• A ray parallel to the axis continues as if coming from the focus.
• A ray passing through the optical center continues without deviation.
• A ray heading towards the focus continues parallel to the axis.
• Objective: Distinguish between convex and concave lenses.
• Success Criteria: Draw particular rays passing through a concave lens

Concave Lenses - Formation of images

• Objective: Draw the image given by a convex and concave lens and list its characteristics.
• Success Criteria: Draw the image of an object given by a concave lens.

Concave Lenses - Formation of images

• Objective: Draw the image given by a convex and concave lens and list its characteristics.
• Success Criteria: Draw the image of an object given by a concave lens.
• The image is always:
  • Virtual
  • Upright
  • Smaller than the object
  • Closer to the lens
• NOTE: This is the case of the judas of a door.

Lens Formula

• f: focal length
• u: object distance
• v: image distance
• Objective: Relate the focal length to the position of the object and that of the image.
• Success Criteria: Apply the lens formula.
• $\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$

Lens Formula - comments

• -u is always positive.
• - If v is positive, then the image is real.
• - If v is negative, then the image is virtual.
• - f is positive for a convex lens and negative for a concave lens.
• Objective: Relate the focal length to the position of the object and that of the image.
• Success Criteria: you will be able to apply the lens formula.
• $\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$

Lens Formula - Magnification

• m = image height (h') / object height(h)
• m = v/u
• If |m| > 1 The image is magnified (larger than the object).
• If |m| < 1 → The image is diminished (smaller than the object).
• Objective: Relate the focal length to the position of the object and that of the image.
• Success Criteria: apply the lens formula.

Application 1

• A convex lens has a focal length of 20 cm. An object is placed 60 cm in front of the lens.
• Questions:
  1. Calculate the image distance v.
  2. Determine the magnification m.
  3. Describe the nature (real/virtual, upright/inverted, magnified/diminished) of the image.
• Objective: Relate the focal length to the position of the object and that of the image.
• Success Criteria: apply the lens formula.
• $\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$

Application 2

• A concave mirror has a focal length of 15 cm. An object is placed 10 cm in front of the mirror.
• Questions:
  1. Calculate the image distance v.
  2. Determine the magnification m.
  3. Describe the nature of the image.

Application 3

• A diverging (concave) lens has a focal length of -25 cm. An object is placed 15 cm in front of the lens.
• Questions:
  1. Calculate the image distance v.
  2. Determine the magnification m.
  3. Describe the nature of the image.

Correction of Vision Defects

• long-sightedness
• Hypermetropia
• Correction: Convex lens
• Objective: Explain how to correct long-sightedness and short-sightedness using lenses.
• Success Criteria: Explain how to correct long-sightedness.

Correction of Vision Defects

• short-sightedness
• Myopia
• Correction: Concave lens
• Objective: Explain how to correct long-sightedness and short-sightedness using lenses.
• Success Criteria: Explain how to correct short-sightedness.

Exercises

Exercises Set 1

1. Converging Lens Ray Diagram
2. Converging Lens Statement
3. Focal Point Diagram
4. Focal Length Representation

Exercises Set 2

5. Converging Lens Image Formation
6. Focal Length Calculation

Exercises Set 3

7. Image Nature and Screen Formation
8. Image Statement: Real/Virtual, Eye Position

Exercies Set 4

9. Sharp Image Production
   A. The image is at the principal focus (focal point) of the lens
   B. The image is bigger than the object
   C. The image is closer to the lens than the object
   D. The image is inverted
10. Real Image Production

Exercies Set 5

11. Image Formation by Diverging Lens
12. Short-sighted Eye

Exercies Set 6

13. Correcting Vision with Lenses
14. Eye Defects Correction

Exercises Set 7

15. Converging Lens Ray Diagram
16. Long-sightedness Correction

Exercises Set 8

17. Eye Defect Correction Methods

Lab Report: Image Formation by a Convex Lens

• Name:
• Class:
• Date:
• Objective:
  • To study the nature, size, and type of image formed by a convex lens for different object positions.
• Apparatus Required:
  • Convex lens, optical bench, light source, screen,
• Theory:
  • A convex lens refracts light rays and converges them to form images. The image characteristics depend on the object's position relative to the lens's focal points.
• Procedure:
  1. Fix the convex lens vertically on the optical bench.
  2. Place the object (candle/needle) at different positions relative to the lens (shown in the table).
  3. Move the screen to get a sharp image and measure the image distance.
  4. Record the image position, size, nature, and type.
  5. Repeat for each object position.

Observation Table:

Interference

Objective

• Explain and analyze the interference of light.

Coherent Sources of Light

• Interference is observed when light waves come from coherent sources.
• Sources are said to be coherent if they have:
  • A constant phase difference
  • The same frequency
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to distinguish between coherent and non-coherent sources of light.

Coherent Sources of Light

• A coherent beam of light contains light waves that are monochromatic and have a constant phase difference
• Monochromatic light consists of light waves of a single frequency
• Laser light is an example of a coherent light source
• Filament lamps produce incoherent light waves
• Note: A coherent source is always monochromatic while a monochromatic source may or may not be a coherent source.
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to distinguish between coherent and non-coherent sources of light.

Conditions of interference

• There are two conditions for interference to occur:
  • The sources of the waves must be coherent, which means they emit identical waves with a constant phase difference.
  • The waves should be monochromatic - they should be of a single wavelength (frequency or color)
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to list the two conditions of interference

Examples

• Automobile Headlights:
  • No interference pattern is observed because headlights are not coherent sources.
  • Headlights are too far apart compared to the wavelengths emitted, so interference maxima and minima would be too closely spaced to be observable.
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to list the two conditions of interference

Examples

• Two characteristics of laser light that make it useful:
  • Lasers are coherent, monochromatic, and directional (narrow beam in a specific direction).
  • Perfect to produce a clear interference pattern.
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to list the two conditions of interference

Constructive and Destructive Interference

• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to distinguish between contructive and destructive interference

Constructive Interference

• WAVEFRONTS TRAVEL TOWARDS EACH OTHER SUPERPOSITION CONSTRUCTIVE INTERFERENCE WAVEFRONTS CONTINUE UNCHANGED
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to distinguish between contructive and destructive interference

Destructive Interference

• SUPERPOSITION DESTRUCTIVE INTERFERENCE WAVEFRONTS CONTINUE UNCHANGED
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to distinguish between contructive and destructive interference

Light Interference

• The distance between the slits in a double-slit setup compared to the distance to the screen from the slits is very small
• Constructive interference is shown as bright fringes on the screen, the highest intensity is in the middle
• Destructive interference is shown as the dark fringes on the screen, these have zero intensity
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to explain the phenomenon of light interference

Light interference - Path Difference

• Two Source Interference Fringes
  • For two-source interference fringes to be observed, the sources of the wave must be:
    • Coherent (constant phase difference)
    • Monochromatic (single wavelength)
• When two waves interfere, the resultant wave depends on the phase difference between the two waves
  • This is proportional to the path difference between the waves which can be written in terms of the wavelength λ of the wave
• As seen from the diagram, the wave from slit $S<em>2$ has to travel slightly further than that from $S</em>1$ to reach the same point on the screen. The difference in distance is the path difference
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to explain the light path difference
• CONSTRUCTIVE INTERFERENCE: PATH DIFFERENCE = nλ
• DESTRUCTIVE INTERFERENCE: PATH DIFFERENCE = $(n + \frac{1}{2}) \lambda$ , WHERE n = 0,1,2,3…

Young's Double Slit Experiment

• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to explain Young's experiment

Young's Double Slit Experiment

• When a monochromatic light source is placed behind a single slit, the light is diffracted producing two light sources at the double slits A and B
• Since both light sources originate from the same primary source, they are coherent and will therefore create an observable interference pattern
• Both diffracted light from the double slits create an interference pattern made up of bright and dark fringes
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to explain Young's experiment

Young's Double Slit Experiment

• Constructive interference occurs at locations xm on either side of the central bright band such that:
  • $m \lambda = \frac{x_m d}{L}$
  • where m = order of maxima = 0, 1, 2 …..
• Objective: Explain and analyse the interference of light.
• Success Criteria: Students are able to explain Young's experiment
• $x = m \frac{\lambda L}{d}$

Young's Double Slit - Application 1

• What happens to the spacing between fringes in a two-slit interference pattern if the following changes are made keeping other variables constant in each case.
  • a. Slit separation is increased.
  • b. Color light is switched from red to blue.
  • c. The monochromatic light is replaced by while light.
  • d. The width of the two slits is increased.

Young's Double Slit - Application 1

• What happens to the spacing between fringes in a two-slit interference pattern if the following changes are made keeping other variables constant in each case.
• a. Slit separation is increased.
  • $x = \frac{\lambda L}{d}$
  • If the slit separation (d) increases, the fringe spacing decreases. Thus we get narrower fringes.
• b. Color light is switched from red to blue.
  • Switching the light from red to blue means the wavelength (λ) of the light has decreased. Again from the equation, a decrease in wavelength causes the fringe spacing to decrease so the fringes are closer to each other.
• c. The monochromatic light is replaced by while light.
  • Colored fringes are formed at the screen if monochromatic light is replaced by the white light.
• d. The width of the two slits is increased.
  • Intensity of light emitted by the slits increases as the width of the slit is increased. Thus, more brighter fringes are formed at the screen on increasing the width of the slits.

Young's Double Slit - Application 2

• A laser is placed in front of a double-slit as shown in the diagram below.
• The laser emits light of wavelength 400 nm. The separation of the maxima P and Q observed on the screen is 15 mm. The distance between the double slit and the screen is 4.5 m. Calculate the separation of the two slits.

Young's Double Slit - Application 2

• STEP 1: DOUBLE SLIT EQUATION
  • $m \lambda = \frac{x_m d}{L}$
• STEP 2: REARRANGE FOR A SEPARATION OF THE TWO SLITS
  • $d = \frac{m \lambda L}{x_m}$
• STEP 3: SUBSTITUTE IN VALUES
  • $d = \frac{(9)(4 \times 10^{-7} m)(4.5 m)}{15 \times 10^{-3} m} = 1.08 \times 10^{-3} m = 1.1 mm$

Exercises

Exercises Set 1

• KPI 14.1
  1. Sunlight: Coherent or Incoherent?
  2. Coherent Light Sources Requirements
• KPI 14.3
  3. Conditions for Light Interference
• KPI 14.4
  4. Why Interference Doesn't occur from Flashlights
  5. Conditions Leading to Destructive Interference

Exercises Set 2

• KPI 14.6
  6. Cause of Bright and Dark Fringes in Double-Slit Experiment
  7. Correct statements about Interference
• KPI 14.8
  8. Pattern Observed with White Light in Young's Experiment
  9. Effect of Wavelength on Fringe Spacing

Exercises Set 3

• KPI 14.10
  10. Calculating Wavelength from Double-Slit Setup
  11. Factor that would cause fringes to be more closely spaced
• KPI 14.11
  12. Wavelength of a light

Exercises Set 4

• 14.1, 14.2, 14.3, 14.4 and 14.6 - Free Response Questions

Exercises Set 5

• KPI 14.10 and 14.12
  • 6 - Violet light
  • 7 - Yellow-orange light
  • 8 - Physics students use laser

Exercises Set 6

• KPI 14. 10, 14.11, 14.12, and 14.9
  • 9 - determine how far apart the slits are.
  • 10 - Young's Double slit experiment

Diffraction

Objective

• Describe and analyse the diffraction of light by a narrow slit and by a grating

Task

• Create a presentation (5 to 7 slides):
  • What is diffraction
  • describe the diffraction pattern (single slit)
  • real picture of diffraction
  • diffraction diagram
  • formula and exercises of application

Single Slit Diffraction

• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able to describe the diffraction of light through a single slit

Single Slit Diffraction

• When light passes through a slit that has two closely spaced edges, a pattern is produced on a screen. This pattern, called a diffraction pattern.
• Single-slit diffraction produces one wide bright central band and narrower, dimmer bands on either side.
• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able to describe the diffraction of light through a single slit

Single Slit Diffraction

• The figure below compares the colors and widths of the central bands produced by the different colors of light.
• The figure below shows the diffraction pattern when light traverses a circular slit
• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able to describe the diffraction images for different colours.

Single Slit Diffraction - Position of dark fringes

• The positions of dark fringes on the screen are given by:
  • $x_m = \frac{m \lambda L}{w}$
    • m: order of the fringe
    • L: distance between the slit and the screen.
    • w: width of the slit
    • λ: wavelength
• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able to find the position of dark fringes.

Single Slit Diffraction - Central Fringe Width

• The width of the central fringe is
  • $2x_1 = \frac{2 \lambda L}{w}$
• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able to find the central fringe width

Single Slit Diffraction - Application 2

• Light of wavelength 500 nm passes through a slit of width 0.2 mm. The diffraction pattern is observed on a screen 1.5 m away.
• Calculate the position of the first and the second dark fringe from the central maximum.
• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able to find the position of dark fringes

Single Slit Diffraction - Application 3

• A laser of wavelength 650 nm shines through a single slit of width 0.15 mm onto a screen 2 m away.
• Calculate the width of the central bright fringe.
• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able to find the central fringe width

Diffraction Grating

• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able describe the diffraction grating pattern

Diffraction Grating

• A diffraction grating is a plate on which there is a very large number of parallel, identical, close-spaced slits
• When monochromatic light is incident on a grating, a pattern of narrow bright fringes is produced on a screen
• This pattern is like that of a two-slit interference pattern, but with much narrower and brighter bands.
• Diffraction gratings can have as many as 10,000 slits per centimeter, which means the spacing between the slits can be as small as $10^{-6}$ m
• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able describe the diffraction grating pattern

Diffraction Grating

• The angles at which the maxima of intensity (constructive interference) are produced can be deduced by the diffraction grating equation
• Questions sometime state the lines per m (or per mm, per nm etc.) on the grating which is represented by the symbol n
• d can be calculated from n using the equation:
  • $d = \frac{1}{n}$
• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able describe the diffraction grating pattern
• $d sin(\theta) = m \lambda$
  • ANGULAR SEPARATION BETWEEN THE ORDER OF MAXIMA (DEGREES)
  • WAVELENGTH OF SOURCE (m)
  • SPACING BETWEEN ADJACENT SLITS (m)
  • ORDER OF MAXIMA
    • m=0,1,2,3…

Diffraction Grating - Angular Seperation

• The angular separation of each maxima is calculated by rearranging the grating equation to make θ the subject
• The angle θ is taken from the center meaning the higher orders are at greater angles
• The angular separation between two angles is found by subtracting the smaller angle from the larger one
• The angular separation between the first and second maxima n₁ and n₂ is $θ<em>2 - θ</em>1$
• Objective: Describe and analyse the diffraction of light by a narrow slit and by a grating.
• Success Criteria: You will be able describe the diffraction grating pattern

Diffraction Grating - Application

• An experiment was set up to investigate light passing through a diffraction grating with a slit spacing of 1.7 μm. The fringe pattern was observed on a screen. The wavelength of the light is 550 nm.
• Calculate the angle α between the two second-order lines.

Diffraction Grating - Application Solution

• $sin \Theta = m \frac{\lambda}{d}$
• $$ =2 x 550 x 10^{-9}

1. 7 x 10^{-6}

• $\Theta = 40.3$
• $\alpha = 2\Theta = 2 \times 40.3 = 80.6$

Comparison between Double slit interference, single slit diffraction and Diffraction Grating

• Double Slit Interference
  • Equally spaced bright and dark fringes.
• Single Slit Diffraction
  • A wide, bright center band forms with narrower, dimmer bands to the side.
  • The width is double that of the other maxima.
• Diffraction Grating
  • Bright bands are extremely narrow and equally spaced, with greater intensities.
  • Dark bands are wider than those produced in the double slit.
  • Cannot use small angle approximation which is used in double slits
• Summary
  • Double Slit Interference
    • Equally spaced bright and dark fringes.
  • Single Slit Diffraction
    • the pattern is a central bright band and lighter side bands of the color of monochromatic light that is used, separated by dark bands.
    • The bright bands are equally spaced.
    • If white light is used, the central band is white, and the side bands show spectra.
    • Bright fringes are wider and less intense than those formed in a grating.
  • Diffraction Grating

Exercises

Exercises Set 1

• KPI 15.1
  1. Type of Pattern in Single-Slit Diffraction
  2. Characteristics of Light Passing Through a Single Slit
• KPI 15.3 and 15.4
  3. Factors Analyzed in Single-Slit Diffraction for Wavelength

Exercises Set 2

• KPI 15.2
  4. Calculating Distance in Single-Slit Diffraction
• KPI 15.3 and 15.4
  5. Factors Analyzed in Single-Slit Diffraction
  6. Width of Central Band Calculation with Green Light

Exercises Set 3

• KPI 15.3 and 15.4
  7. Width of Central Bright Band Calculation with Given Parameters
• KPI 15.5
  8. Width of Central Bright Band Change with Distance
• KPI 15.5
  9. Effect of Doubling Slit Width on Central Band Width
  10. Ranking Diffraction Extent Based on Light and Slit Width

Exercises Set 4

• KPI 15.7
  11. Cause of Interference Patterns in Diffraction Grating
  12. Purpose of Closely Spaced Slits in Diffraction Grating
• KPI 15.8
  13. Calculating Distance Between Lines on a Diffraction Grating

Exercises Set 5

• KPI 15.9
  14. Angle of First-Order Bright Line Calculation
  15. Slit Separation Calculation in Grating Spectroscope

Exercises Set 6

• KPI 15.9
  16. Diffraction Angle Calculation with Grating
• KPI 15.8
  17. Number of Slits Production for Narrowest Lines on Diffraction Grating
• KPI 15.9
  18. Total Number of Slits on Grating Production

Exercises Set 7

• KPI 15.4 and 15.5
  1. Calculating Wavelength and Identifying Widest Central Maximum In-Single Slit Diffraction

Exercises Set 8

• KPI 15.2
  1. Calculate the wavelength of light projected on screen
• KPI 15.4
  2. Calculation Of light width central bright band

Exercises Set 9

• KPI 15.8 and 15.12
  1. Find the slit spacing for the grating
  2. What is the highest order maximum that is possible when the light has a wavelength of 400 nm

Exercises Set 10

• KPI 15.9 and 15.11
  1. Find the angels at which one would observe the second-order maximum
  2. If the spacing between lines on a grating is increased, does the angle to the first-order principal maximum increase, decrease, or stay the same?

Exercises Set 11

• KPI 15.6 and 15.9
  1. In the table below, list all the characteristics of double slit interference pattern, single slit diffraction and the diffraction grating pattern

Polarization

Objective

• Explain and analyze the polarisation of light

Polarization of Light

• Transverse waves can oscillate in any plane perpendicular to the direction of motion of the wave
  • Such waves are said to be unpolarized
• Polarization occurs when particles are only allowed to oscillate in one of the directions perpendicular to the direction of wave propagation
• When a transverse wave is polarized, its electric field is only allowed to oscillate in one fixed plane perpendicular to the direction of motion of the wave.

Polarization of light

• A transverse wave can be vertically polarized, horizontally polarized, or polarized in any direction in between
• Since longitudinal waves oscillate in the same direction as the direction of motion of the wave, polarization of longitudinal waves cannot occur
• Methods of polarization include polarizing filters and reflection from a non-metallic plane surface

Polarizing Filters

• Light waves can be polarized by making them pass through a polarizing filter (also known as a polarizer)
• The filter imposes its plane of polarization on the incident light wave
• A polarizer with a vertical transmission axis only allows vertical oscillations to be transmitted through the filter
• If vertically polarized light is incident on a filter with a horizontal transmission axis, no transmission occurs, and the wave is blocked completely

Polarizing Filters

• Light can also be polarized through reflection, refraction and scattering
• An example of polarization in everyday life is polaroid sunglasses.
  • These reduce glare caused by sunlight for drivers to see through windows and fishermen to see beneath the water surface more clearly

Malus's law

• If unpolarized light of intensity I, passes through a polarizer, the intensity of the transmitted polarized light falls by a half
• The first filter that the unpolarized light goes through is the polarizer
• A second filter placed after the first one is known as an analyzer
• Note:
  • $I' = \frac{I}{2}$
  • $I''= I' Cos^2(\theta)$
  • $I$ is the inetensity of light in W/$m^2$

Malus's law - Application 1

• Unpolarized light of intensity I = 200W/$m^2$ passes through polarizer, and then through an analyzer whose axis is rotated 30° relative to the polarizer's axis.
• Calculate the final intensity of the light emerging from the analyzer.

Malus's law - Application 1 Solution

• First polariser:
  • $I<em>1= I</em>0/2$
  • $I_1= 200/2 = 100 W/m^2$
• Second Polariser: