Stimulated emission

Sources: http://en.wikipedia.org/wiki/Absorption_%28electromagnetic_radiation%29 http://hyperphysics.phy-astr.gsu.edu/hbase/biology/ligabs.html http://www.physicsclassroom.com/class/light/u12l2c.cfm http://www.andor.com/learning/light/?docid=333 http://www.chemicool.com/definition/absorption_of_light.html http://hyperphysics.phy-astr.gsu.edu/hbase/biology/photosyn.html#c1

Q5. List the factors on which the angle of deviation through a prism depends. Ans: Following are the factors on which the angle of deviation through a prism depends:

We have written many articles about the absorption of light for Universe Today. Here’s an article about absorption spectra, and here’s an article about absorption spectroscopy.

Absorptionspectrum

As already noted, absorption depends upon the state of an objects electrons. All electrons are known to vibrate at specific frequencies, what is commonly known as their natural frequency. When light, in the form of photons, interacts with an atom with the same natural frequency, the electrons of that atom will become excited and set into a natural vibrational motion. During this vibration, the electrons of the atom interact with neighboring atoms in such a way as to convert this vibrational energy into thermal energy. Subsequently, the light energy is not to be seen again, hence why absorption is differentiated from reflection and transmission. And since different atoms and molecules have different natural frequencies of vibration, they will selectively absorb different frequencies of visible light.

Q6. What happens to the incident ray when it enters the prism? Ans: When an incident ray enters the prism, it bends towards the normal as it changes its path and gets deviated.

Transmittance

Two-photonabsorption

Q2. What is the unit of the refractive index? Ans: Refractive index has no unit. This is because it is a ratio between the speed of light in vacuum and in a medium.

If you’d like more info on light absorption, check out an article about Light Absorption, Reflection, and Transmission. Also, here’s an article about reflection and absorption of light.

A prism is a transparent optical object with two flat surfaces that have an angle between them. When the light enters the prism, there is a bending of light as there is a change in the speed of light. The bending of the light is dependent on the angle of incidence, normal, and refractive indices. There are four different types of angles involved in this experiment, and they are the angle of incidence, angle of emergence, angle of prism and angle of deviation. Below is an experiment to trace the path of a light ray through a glass prism.

Attenuation coefficient

Waterabsorptionspectrum

We’ve also recorded an entire episode of Astronomy Cast all about Energy Levels and Spectra. Listen here, Episode 139: Energy Levels and Spectra.

By relying on this method, physicists are able to determine the properties and material composition of an object by seeing which frequencies of light it is able to absorb. Whereas some materials are opaque to some wavelengths of light, they transparent to others. Wood, for example, is opaque to all forms of visible light. Glass and water, on the other hand, are opaque to ultraviolet light, but transparent to visible light.

Absorbance

Q1. What is refractive index? Ans: Refractive index is defined as the ratio between the sine of the angle of incident ray i in a vacuum to the sine of the angle of refraction r in a given medium. The mathematical representation of the refractive index is given as:

Q4. What is the dispersion of light? Ans: The dispersion of light is defined as the phenomenon of splitting white light into its seven constituent colours when it is made to pass through a transparent medium.

[/caption] Those who can remember sitting through elementary science class might recall learning that with all matter, light is absorbed and converted into energy. In the case of plants, this process is known as photosynthesis. However, they are by no means the only species or objects that do this. In truth, all objects, living or inorganic are capable of absorbing light. In all cases, absorption depends on the electromagnetic frequency of the light being transmitted (i.e. the color) and the nature of the atoms of the object. If they are complementary, light will be absorbed; if they are not, then the light will be reflected or transmitted. In most cases, these processes occur simultaneously and to varying degrees, since light is usually transmitted at various frequencies. Therefore most objects will selectively absorb light while also transmitting and/or reflecting some of it. Wherever absorption occurs, heat energy is generated.

A prism is defined as a polyhedron with a triangular base and three rectangular lateral surfaces. It is used as an optical object to study the behaviour of white light when it is passed through it. The light bends at various angles like an angle of incidence, angle of reflection, angle of refraction, and angle of deviation.

Ultimately, absorption of electromagnetic radiation requires the generation of the opposite field, in other words, the field which has the opposite coefficient in the same mode. A good demonstration of this is color. If a material or matter absorbs light of certain wavelengths (or colors) of the spectrum, an observer will not see these colors in the reflected light. On the other hand if certain wavelengths of colors are reflected from the material, an observer will see them and see the material in those colors. For example, the leaves of green plants contain a pigment called chlorophyll, which absorbs the blue and red colors of the spectrum and reflects the green. Leaves therefore appear green, whereas reflected light often appears to the naked eye to be refracted into several colors of the spectrum (i.e. a rainbow effect).