Quiz: Relationship Between Refractive Index & Speed of Light

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Questions and Answers

What is the relationship between the speed of propagation in a medium and the speed of light in a vacuum?

c = c0/n

What is the refractive index for glass?

1.5

What is the refractive index for water?

1.33

What is the relationship between frequency and the medium through which an electromagnetic wave travels?

Frequency depends only on the source and is independent of the medium. Signup and view all the answers

What did Max Planck propose in 1900 regarding electromagnetic radiation?

He proposed that electromagnetic radiation consists of discrete packets of energy called photons or quanta. Signup and view all the answers

What is the energy of a photon related to?

The energy of a photon is inversely proportional to its wavelength. Signup and view all the answers

What law gives the wavelength at which the peak occurs for a specified temperature?

Wien's displacement law Signup and view all the answers

What law gives the total radiation emitted by a blackbody at all wavelengths?

Stefan-Boltzmann law Signup and view all the answers

What is radiation intensity defined as?

The rate of energy leaving a surface in a given direction per unit solid angle per unit area of the emitting surface normal to the mean direction in space. Signup and view all the answers

How is the direction of radiation passing through a point best described?

In spherical coordinates in terms of the zenith angle θ and the azimuth angle ϕ. Signup and view all the answers

What does the function fλ represent?

The fraction of radiation emitted from a blackbody at temperature T in the wavelength band from λ = 0 to λ. Signup and view all the answers

What is the intensity of radiation streaming through a surface area dS proportional to?

The solid angle dω subtended by dS. Signup and view all the answers

What is the speed of electromagnetic waves in a vacuum?

The speed of electromagnetic waves in a vacuum is 2.9979 x 10^8 m/s. Signup and view all the answers

How are electromagnetic waves characterized?

Electromagnetic waves are characterized by their frequency $\nu$ or wavelength $\lambda$. Signup and view all the answers

According to Maxwell's theory, what gives rise to electromagnetic waves?

According to Maxwell's theory, accelerated charges or changing electric currents give rise to electric and magnetic fields, which propagate as electromagnetic waves. Signup and view all the answers

How do electromagnetic waves transport energy?

Electromagnetic waves transport energy in the same way as other waves, by propagating through space. Signup and view all the answers

What is the relationship between the frequency and wavelength of an electromagnetic wave?

The frequency $\nu$ and wavelength $\lambda$ of an electromagnetic wave are related by the equation $c = \nu \lambda$, where $c$ is the speed of light. Signup and view all the answers

Can electromagnetic waves travel through a vacuum?

Yes, electromagnetic waves can travel through a vacuum without requiring a material medium. Signup and view all the answers

Study Notes

Electromagnetic Waves

The speed of propagation in a medium is related to the speed of light in a vacuum by c = c0/n, where n is the index of refraction of that medium.
Refractive index is essentially unity for air and most gases, about 1.5 for glass, and about 1.33 for water.
The commonly used unit of wavelength is the micrometer (μm) or micron, where 1 μm = 10-6 m.
Frequency of an electromagnetic wave depends only on the source and is independent of the medium through which the wave travels.

History of Electromagnetic Waves

Max Planck in 1900 proposed electromagnetic radiation as the propagation of a collection of discrete packets of energy called photons or quanta.
Each photon of frequency (ν) has an energy of e = hν = hc/λ, where h is Planck's constant.
Energy of a photon is inversely proportional to its wavelength, so shorter-wavelength radiation possesses larger photon energies.

Blackbody Radiation

Wien's displacement law states that the wavelength at which the peak occurs for a specified temperature is given by λTmax.power = 2897.8 μm.K.
Stefan-Boltzmann law Eb(T) = σT4 gives the total radiation emitted by a blackbody at all wavelengths from λ = 0 to λ = ∞.
Function fλ represents the fraction of radiation emitted from a blackbody at temperature T in the wavelength band from λ = 0 to λ.

Radiation Intensity

Intensity of radiation (I) is defined as the rate of energy leaving a surface in a given direction per unit solid angle per unit area of the emitting surface normal to the mean direction in space.
Direction of radiation passing through a point is best described in spherical coordinates in terms of the zenith angle θ and the azimuth angle ϕ.

Solid Angle

Differential surface area on a sphere is given by dS = r2sinθ dθdϕ.
Solid angle can be found by integrating dS from θ = 0 to θ = π and ϕ = 0 to ϕ = 2π.

Unit III: Radiation

Kirchhoff's Law, Planck's Distribution Law, Wien's Displacement Law, Stefan-Boltzmann's Relation, and Configuration Factor are important concepts in radiation.
Radiation can occur between two bodies separated by a medium colder than both bodies.
Solar radiation reaches the surface of the earth after passing through cold air layers at high altitudes.

Introduction to Radiation

Radiation is a type of energy transfer that does not require a material medium.
Energy is transferred by electromagnetic waves at the speed of light, with no attenuation in a vacuum.
Radiation heat transfer can occur between two bodies separated by a medium colder than both bodies.

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Description

Explore the relationship between the speed of propagation in a medium and the speed of light in vacuum through the refractive index. Learn about the refractive indexes of various mediums like air, glass, and water, and understand the unit of wavelength in micrometers.