/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 44 (a) A transparent plate with ind... [FREE SOLUTION] | 91Ó°ÊÓ

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(a) A transparent plate with index of refraction \(n_{2}\) is immersed in a medium with index \(n_{1}\). Light traveling in the surrounding medium strikes the top surface of the plate at Brewster's angle. Show that if and only if the surfaces of the plate are parallel, the refracted light will strike the bottom surface of the plate at Brewster's angle for that interface. (b) What If? Instead of a plate, consider a prism of index of refraction \(n_{2}\) separating media of different refractive indices \(n_{1}\) and \(n_{3} .\) Is there one particular apex angle between the surfaces of the prism for which light can fall on both of its surfaces at Brewster's angle as it passes through the prism? If so, determine it.

Short Answer

Expert verified
In conclusion, (a) The refracted light will strike the bottom surface of the plate at Brewster’s angle if and only if the plate surfaces are parallel and the refractive indices \(n_1\) and \(n_2\) of the media are equal. (b) There exists a prism geometry allowing for similar Brewster's angles on both surfaces, and it would have an apex angle \(φ = 2(90 - arctan(n_2/n_1))\).

Step by step solution

01

Analyzing and Formulating for Part (a)

Brewster's angle (\(θ_B\)) is the angle of incidence at which light is polarized parallel to the incident plane. It is given by \(tan θ_B = n_2/n_1\), where \(n_1\) and \(n_2\) are refractive indices of the media. Using Snell's law we know, \(n_1 sin θ_i = n_2 sin θ_r\). For the light to strike the bottom surface of the plate at Brewster's angle, the angles of incidence and refraction must be equal, i.e \(θ_i = θ_r = θ_B\).
02

Applying Formulas for Part (a)

It is known from Snell's Law that \(n_1 sin θ_i = n_2 sin θ_r\). Given \(θ_i = θ_B = θ_r\) (from previous step requirement), we substitute into the Snell’s law. We get \(n_1 sin θ_B = n_2 sin θ_B\). This equation will hold true only when \(n_1 = n_2\), thus when indices are the same, the refracted light will strike the bottom surface of the plate at Brewster's angle provided the plate surfaces are parallel.
03

Analyzing and Formulating for Part (b)

From the analysis of part (a), one concludes that the Brewster's angle can only be the same through two interfaces if the indices of refraction are equal. In the case of the prism, the apex angle (\(φ\)) will be the internal angle at which the light reflects. If the light strikes both interfaces at the Brewster's angle, the angle of refraction at both interfaces is \(90-θ_B\) (considering angle in a right triangle). Thus, the apex angle of the prism is equal to twice the angle of refraction.
04

Applying Formulas for Part (b)

Using the relationship established in step 3, the apex angle (\(φ\)) of the prism can be expressed as \(φ = 2r = 2(90 - θ_B)\). Substituting the expression for Brewster's angle \(θ_B\), we get \(φ = 2(90 - arctan(n_2/n_1))\), which gives the value of the required apex angle for which light can fall on both surfaces at Brewster's angle.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Snell's Law
Snell's Law is a fundamental principle in optics that describes the behavior of light as it passes from one medium to another. It tells us how much the light bends, or refracts, at the boundary between two different mediums. The law is expressed mathematically as:
  • \[ n_1 \sin \theta_1 = n_2 \sin \theta_2 \]
Here, \( n_1 \) and \( n_2 \) are the refractive indices of the first and second media, respectively. \( \theta_1 \) is the angle of incidence, and \( \theta_2 \) is the angle of refraction. The refractive index quantifies how much light bends, with higher values indicating more bending.

Understanding Snell's Law helps to solve problems involving refraction at surfaces, like when light encounters a transparent plate or a prism. For example, when light enters at Brewster's angle, Snell's Law ensures the angle of refraction satisfies the condition for minimizing reflection.
  • Brewster's angle is special because it results in light that becomes perfectly polarized.
  • This condition allows us to deduce relationships between incident and refracted angles for specific tasks, like ensuring light strikes another surface at Brewster's angle.
  • It's particularly useful in optics design, where controlling light propagation is crucial.
Refractive Index
The refractive index is a measure of how much light slows down as it travels through a medium. It's denoted by \( n \) and affects how light bends as it enters a new medium. The refractive index of a medium is defined relative to the speed of light in a vacuum, where:
  • \[ n = \frac{c}{v} \]
Here, \( c \) is the speed of light in a vacuum and \( v \) is the speed of light in the medium. A higher refractive index means light travels slower through the medium, causing more bending.When considering optical components:
  • The refractive index directly influences optical phenomena like refraction and reflection.
  • It is crucial for determining Brewster's angle, where \( \tan \theta_B = \frac{n_2}{n_1} \)
  • A uniform refractive index across a medium ensures symmetrical refraction patterns, as seen in parallel surfaces or symmetric prisms.
Understanding refractive indices is essential for designing lenses, prisms, and other optical devices to guide light in precise ways.

It's also important in explaining why certain angles lead to no reflection, making Brewster's angle feasible under specific conditions, especially when two interfaces have similar refractive indices.
Prism Optics
Prism optics is the study of how prisms interact with light. A prism is a transparent optical element with flat, polished surfaces that refract light. The key parameters in prism optics include the angles of its surfaces and the refractive index of the material. These factors influence how light is refracted and dispersed.

Prisms are known for their ability to split light into a spectrum, but they can also bend light at specific angles, such as Brewster's angle. This angle ensures that light within the prism is polarized.
  • In a prism, the apex angle is significant, as it determines the light path within the prism.
  • To find an apex angle where Brewster's angle is achieved on both surfaces, we need to consider the light path symmetry.
  • Understanding the relationship between the angle of incidence, refractive indices, and apex angle allows for precise control of light as it traverses a prism.
Prism optics finds applications in many areas, such as spectroscopy and laser systems, where control over light direction and polarization is vital. In specific cases, such as achieving Brewster's angle, the prism can be manipulated to ensure light optimization through its surfaces.

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Most popular questions from this chapter

A wide beam of laser light with a wavelength of \(632.8 \mathrm{nm}\) is directed through several narrow parallel slits, separated by \(1.20 \mathrm{mm},\) and falls on a sheet of photographic film \(1.40 \mathrm{m}\) away. The exposure time is chosen so that the film stays unexposed everywhere except at the central region of each bright fringe. (a) Find the distance between these interference maxima. The film is printed as a transparency-it is opaque everywhere except at the exposed lines. Next, the same beam of laser light is directed through the transparency and allowed to fall on a screen \(1.40 \mathrm{m}\) beyond. (b) Argue that several narrow parallel bright regions, separated by \(1.20 \mathrm{mm},\) will appear on the screen, as real images of the original slits. If at last the screen is removed, light will diverge from the images of the original slits with the same reconstructed wave fronts as the original slits produced. (Suggestion: You may find it useful to draw diagrams similar to Figure \(38.16 .\) A train of thought like this, at a soccer game, led Dennis Gabor to the invention of holography.)

A helium-neon laser emits light that has a wavelength of \(632.8 \mathrm{nm} .\) The circular aperture through which the beam emerges has a diameter of \(0.500 \mathrm{cm} .\) Estimate the diameter of the beam \(10.0 \mathrm{km}\) from the laser.

Narrow, parallel, glowing gas-filled tubes in a variety of colors form block letters to spell out the name of a night club. Adjacent tubes are all \(2.80 \mathrm{cm}\) apart. The tubes forming one letter are filled with neon and radiate predominantly red light with a wavelength of \(640 \mathrm{nm}\). For another letter, the tubes emit predominantly violet light at \(440 \mathrm{nm}\). The pupil of a dark-adapted viewer's eye is \(5.20 \mathrm{mm}\) in diameter. If she is in a certain range of distances away, the viewer can resolve the separate tubes of one color but not the other. Which color is easier to resolve? The viewer's distance must be in what range for her to resolve the tubes of only one color?

White light is spread out into its spectral components by a diffraction grating. If the grating has 2000 grooves per centimeter, at what angle does red light of wavelength 640 nm appear in first order?

The critical angle for total internal reflection for sapphire surrounded by air is \(34.4^{\circ} .\) Calculate the polarizing angle for sapphire.

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