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Questions and Answers
What range of wavelengths characterizes the visible spectrum?
What range of wavelengths characterizes the visible spectrum?
- Approximately $4 \times 10^{-7}$ to $7 \times 10^{-7}$ meters (correct)
- Approximately $1 \times 10^{-9}$ to $3 \times 10^{-9}$ meters
- Approximately $8 \times 10^{-3}$ to $1 \times 10^{-2}$ meters
- Approximately $2 \times 10^{-5}$ to $5 \times 10^{-5}$ meters
Which color within the visible spectrum has the longest wavelength?
Which color within the visible spectrum has the longest wavelength?
- Blue
- Green
- Violet
- Red (correct)
If radiation with a wavelength of $5 \times 10^{-7}$ meters is passed through a prism, what would be the most likely observed outcome?
If radiation with a wavelength of $5 \times 10^{-7}$ meters is passed through a prism, what would be the most likely observed outcome?
- It would pass straight through the prism without any change in direction or appearance.
- It would be refracted and perceived as a color within the visible spectrum. (correct)
- It would be invisible, as it falls outside the visible spectrum.
- It would be absorbed by the prism material.
A scientist is studying electromagnetic radiation and detects a wave with a wavelength of $3 \times 10^{-7}$ meters. Based on your understanding, what is the most accurate conclusion?
A scientist is studying electromagnetic radiation and detects a wave with a wavelength of $3 \times 10^{-7}$ meters. Based on your understanding, what is the most accurate conclusion?
Imagine a scenario where the range of the visible spectrum shifts such that it encompasses wavelengths from $1 \times 10^{-8}$ to $3 \times 10^{-8}$ meters. How would this altered visible spectrum MOST profoundly impact our perception of the universe?
Imagine a scenario where the range of the visible spectrum shifts such that it encompasses wavelengths from $1 \times 10^{-8}$ to $3 \times 10^{-8}$ meters. How would this altered visible spectrum MOST profoundly impact our perception of the universe?
What is the approximate critical angle for light traveling from glass (n=1.50) into air (n=1.00)?
What is the approximate critical angle for light traveling from glass (n=1.50) into air (n=1.00)?
Which statement accurately describes the propagation of light?
Which statement accurately describes the propagation of light?
Which principle is described by stating a light ray follows the path of least time between two points?
Which principle is described by stating a light ray follows the path of least time between two points?
Imagine a scenario where light is used to transmit data through an optical fiber with varying refractive indices. According to Fermat’s Principle, which of the following fiber designs would ensure the fastest data transmission?
Imagine a scenario where light is used to transmit data through an optical fiber with varying refractive indices. According to Fermat’s Principle, which of the following fiber designs would ensure the fastest data transmission?
Consider a complex lens system designed to correct for chromatic aberration. The system consists of multiple lenses with different refractive indices and dispersion properties. If a ray of white light enters the system, which of the following scenarios best demonstrates an application of the principles of both Huygens and Fermat?
Consider a complex lens system designed to correct for chromatic aberration. The system consists of multiple lenses with different refractive indices and dispersion properties. If a ray of white light enters the system, which of the following scenarios best demonstrates an application of the principles of both Huygens and Fermat?
Flashcards
Light Travel Mediums
Light Travel Mediums
Light can travel through both air and a vacuum.
Huygens's Principle
Huygens's Principle
False. Fermat's Principle states that light takes the path of least time.
Fermat's Principle
Fermat's Principle
Light always takes the quickest path between two points.
Huygens's Principle
Huygens's Principle
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Law of Reflection
Law of Reflection
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Visible Light
Visible Light
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Wavelength Range of Visible Light
Wavelength Range of Visible Light
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Colors in the Visible Spectrum
Colors in the Visible Spectrum
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Electromagnetic Radiation
Electromagnetic Radiation
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Wavelength
Wavelength
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Study Notes
Optics
- Optics is closely linked to human civilization's progress since ancient times.
Historical Stages of Optics
- Greek Philosophers: They were the first to attempt explaining vision and light, referring to optics as "Optics" but their research lacked depth and relied on philosophy rather than experimentation, believing reason could determine truth.
- Scientists in the Islamic Era: Hasan Ibn al-Haytham, known as Alhazen, was a pioneer. He emphasized experimental methodology, and is credited with founding the science of optics. His writings became essential resources for European universities, defining light and explaining vision.
- Modern Renaissance: Europeans invented the telescope and microscope, and made key discoveries in light properties with contributions from Snell, Descartes, and Fermat. Two competing theories emerged: one viewing light as particles which came from al-Haytham, Newton, and the other from Huygens, conceptualizing light as waves.
- Electromagnetic Spectrum: Maxwell identified a connection between electricity and magnetism. Moving electric charges produce magnetic fields and fluctuating magnetic fields generate electric fields. He derived a wave equation, calculating the speed of electromagnetic waves(3x10^8 m/s), matching light's speed and proving light behaves as a wave. Hertz confirmed this in 1888, showing energy radiates from oscillating circuits without physical connections, forming the basis for wireless communication.
- Up to 1913, light was considered a wave, but understanding light emission from atoms remained limited until Bohr offered a quantum-based explanation for light emission. The quantum theory was born.
- Light's nature involves both particles and waves—confirmed by de Broglie's work at age 31 establishing the relation between these properties. In 1925, reliance on quantum theory grew.
- Optics is divided into geometric, wave, and quantum optics.
- Geometric optics
- Wave optics
- Quantum optics
Significance of Optics Study
- The study of optics, including fiber optics and lasers, is crucial for engineering students across disciplines, offering a broad base in optical communication networks and more.
The Nature of Light and Laws of Geometric Optics
Introduction
- Light travels from one point to another, and is a unique wave. It is explained by:
- Particle theory (Newton's corpuscular theory)
- Huygens's wave theory
- Electromagnetic wave theory
- Quantum theory
Particle theory
- Light consists of tiny particles called corpuscles, which are emitted from a luminous source.
- Corpuscles travel at very high speed.
- When reaching the retina of the eye, they produce the sensation of vision.
- This theory explains the rectilinear propagation of light because the size of the particles is so small that Earth's gravitation has little effect on them.
- It gives explanations of the laws of reflection and refraction.
- It fails to explain the phenomenon of interference, diffraction, and polarization.
Huygens's wave theory
- Light is a form of longitudinal waves, that can explain the reflection, refraction, interference, and diffraction.
- It could not properly explain the phenomenon of polarization.
- Huygens's Principle: Every point on a given wave front can be considered as a point source for a secondary wavelet. At sometime later, the new position of the wave front is determined by the surface tangent to the set of secondary wavelets.
Electromagnetic wave theory
- Fresnel and Young proposed light waves are transverse in nature, and if V is the velocity through an elastic medium including elasticity E and density p, then V = √E/ρ, ether has very high elasticity and low density.
- Light can travel without any medium.
- Electromagnetic waves where V = 1/√εμ, with ɛ as dielectric constant and µ as the medium's permeability. Definite values for vacuum exist, negating hypothetical need.
Quantum theory
- Until the 20th century, all characteristics of light had been explained, and why light from a particular source gave same set of wavelengths remained a problem.
- Light's dual character includes both wave and quantum theories.
- Either of the two theories alone cannot give the complete nature of light.
Fermats Principle
- This states: A light ray traveling between any two points will follow a path which requires the least time.
- Fermat's principle is sometimes called the principle of least time.
Reflection
- Incident and reflected light both obey simple laws:
- The incident ray, the reflected ray, and the normal all lie in the interface separating each media.
- Angle of incidence mirrors the angle of reflection as in Figure.
Refraction
- Refraction happens because light proceeds at variant speeds in the media.
- Snell's Law dictates: n₁ sin ₁ = n₂ sin ₂, where n₁, n₂ represent refractive indices.
- Angles are of incidence and refraction.
- C indicates speed within a vacuum with its division by v₁ and v₂ of media speeds reflecting n₁ and n₂.
- Angles are measured relative to the normal.
Refractive index
- When a light ray or a wavefront incidents at 90° towards two media’s barrier no refraction surfaces.
Reversibility of light
- "Light traveling from A to B via a system can reverse its path from B to A via it where <x = , <y = <r.
Change in wavelength
- If the medium is slower the new wave front Cd will not be parallel with the wave.
- From Snell's now formula nI sin i = nn sin r. The air constant equals Nn= 1 for then
Critical Angle and Total Internal Reflection
- Angles made in mediums and the air are most of the time greater when the light is not emitted from the denser mediums it’s often reflected that obeys the formula nI sin c = nn sin 90° in the case of an internally refracting prism, and it can use Snell's law.
Right-angled isosceles prism
- An object often used with light where the main concept it often totally reflects as the mirror doesn’t often absorb the reflective.
Optical fibers
- Fibers are often an interesting application of total internal reflection of the use of good quality plastic or to put them into and out of areas.
Light Dispersion and Electromagnetic Spectrum
Dispersion and Prisms
- Glass lenses are a design complication for light where refractive level stays consistent, however it’s function of wave lengths this issue is called dispersion.
- When its goes through the prism is bended from 2 services by angle of derivation delta varies by lengths.
Electromagnetic Spectrum
- Light is a part of numerous flying spectrum from space so electromagnetic energy travels there regardless of if the eyes.
- All are in the form of electricity or waves that travel at light.
- Gamma rays have wavelengths from about 10^-11m or below and emitted from a radioactive nucleus and can damage human cells.
- X-rays have wavelengths from about 10^-11 to 10^-8 and can be used in medicine to produce pictures of internal organs.
- Ultraviolet radiation ranges in wavelength from 10^-8 to 4x10^-7m and produces a carbon arc lamp.
- Visible light spans wavelengths 4x10^-7 to 7x10^-7 and comes mostly from the sun and can be detected without photo electrical cells.
- Infrared radiation has wavelengths from 7x10^-7 to 10^-3 and is often measured using a thermal detector.
- Radiowaves are lengths ranging from 10^-3 to 10^5 . This type can be used in communications as these are also affected by electricity.
Power of light
- The fundamental unit of optical power, the watt (W). It is defined as a rate of energy of one joule (J) per second but the wattage is changed. The rate of energy it described by the formula E=H/a.
- Lumen in (IM) it the equivalent photometric of weight based observer yellow light. – 1watt = 555 mm=683.0 of Iummens
Properties of all forms of electromagnetic radiation
- All transverse waves travel in free space at c= 3x10power8.
- The wave function all under suitable conditions can interfere.
- This type of light doesn’t mean it can travel though mediums all the time. This light can often polarize.
Interference of Light Waves
Introduction to Interference
- Interference is one of the phenomena when two light sources can cross without producing any modifications. Instead the intensity and amplitude may be different. This effect in addition to superposition often gives 2 or more of a beam it be called interference
Young's Double-Slit Experiment
- Thomas Young's experiment demonstrated light interference.
- Light passes through two small slits (S1 and S2) to allow an analysis with a light source and the geometry used to see how much the light wave optics.
Theory of Interference Fringes
- It's not possible to have two completely independent sources as the 2 dual wave lengths can often come from a source that often be coherent.
- Consider these single wave lengths. In front of a single source that’s equivalent to a double distance, the wavelength and source are said to show a 2 achromatic coherent source
Intensity Pattern
- If there are 2 waves that are in the start in the same area, if there’s a start to when things arrived it will be said it had a path ways for lights and waves.
Change of Phase Due to Reflection
- Electromagnetic wave experiences the start of the change of one of the mediums from one point in addition to the reflective.
Interference in Thin Films
- Films have change in thickness with many wave length, therefore there’s one case of 2 to a file surrounded on a common medium
- There is a 180 degree change where the rays in phase.
- 2 NT =( m+ 1/2)
Methods of Getting Interference Pattern Fresnel’s Biprism
- A biprism is often used in an prism to show one phenomenon this will include 2 angle prisms to do their actions on a wave. Theory:
- The point is often the same as a beam to cause all sides all alternate in bright ways
- It in simple ducted with waves, where it shows with length of brighness equal to the wave
Michelson interferometer
- It is an interference system that uses wave splitters to work other patterns
- Principle beam of system in the source is divided by to equal the intensity
Application of Michelson interferometer
- To allow 2 different types to do their functions on a testing system
- For the refractors and thickness on the outside materials.
- Wave Length is given a monochromatic light.
Diffraction
The Diffraction Grating
- Diffraction grating is a device with extremely narrow and closely spaced slits, used in science and technology to measure wavelengths giving accurate analysis.
- The path difference between waves from two adjacent slits equals d sin θ .
- The equation below can also be use to compute the wave (d sin θ = mλ (m = 0,1,2,.....)
- M is the number to the pattern wave for refraction
- Angle zero is set under to maxima where theta is measured.
- There are many functions about grating such as the many levels of a design
The Diffraction Grating The diffraction grating is essentially a multiple
- Slit device in science use to measure wave length with high levels of accurate.
- The wave is equal to distance, therefore what can vary where distance and source
Fraunhofer Diffraction at a Single Slit
- To look at what can come from a refraction is to get a wave in area that gives an convex wave length.
The Diffraction Pattern
- The values of it the one point the width as the slit, also the same way is the wave is equal.
Fraunhofer Diffraction at a Double Slit
- For a 2 Slit source the source have to first the medium as they meet and mix
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