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CBSE Class 12 » CBSE Class 12 Study Materials » Physics » Line Spectra
CBSE

Line Spectra

Line spectra in physics is the study of light waves that are produced by many materials, such as stars, gases, liquids and solids.

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Introduction

The Line Spectra is a visual representation of the colour spectrum. Each line has a specific colour, usually ranging from blue to red, representing the brightness level of colours in that range. Every painting or drawing has a certain range of colours, and it is often seen in lines. The Line Spectra can be used to find colours that are similar to one another, such as blue and green. Spectral lines are dark or bright lines caused by light being emitted or absorbed in a narrow frequency range. They’re often used to identify atoms and can help in other ways. 

Details about the Line Spectra Types

Line Spectra are lines that can be found on a spectrum of energy. They help define the energy levels at which the photon is found and can vary in their width due to how they were created. The photon only has the right amount of energy to change the system when it has enough frequency. When this happens, there’s an electron in orbitals that it will affect. Then, spontaneously emitted at the same frequency as the cascade or the original photon, the total emitted photon energy is equal to the absorbed photon energy. 

Line Spectra are often observed as either absorption or emission lines. The type of spectral line seen would depend on the type of fabric and its temperature relative to the source of emission. Absorption lines are Line Spectra that form when photons pass through objects. They usually have a sharp profile in the gamma-ray spectrum and can identify materials with a higher proportion of matter at lower temperatures, such as soot. 

Light is a form of electromagnetic radiation with wavelengths longer than radio waves but shorter than visible light waves. Its waves are often in the ultraviolet and infrared parts of the spectrum. In general, an optical phenomenon called total internal reflection occurs when light bounces off a denser medium such as water or glass and enters into a less dense medium such as air or vacuum. 

Photons are the particles of light, and an emission spectrum line is created when photons are observed in some material with a broad spectrum. When photons from some of the hot material are observed in the presence of a broad spectrum from a cold source, an emission spectrum line is formed. This is what causes an increase in light intensity.

Line Spectra are the ongoing emission or absorption of electromagnetic radiation from a medium. Scientists use spectroscopy to help identify many elements, such as thallium, caesium, and helium. Spectral lines are among the most important tools used in astronomy and astrophysics. They help scientists determine how molecules are distributed throughout space, and how the outer layers of stars and galaxies interact. 

About Line broadening and shift in line spectra

Several factors influence the form of a spectral line. A Line Spectra is a line that spans a frequency range rather than a single frequency (it means it has a nonzero linewidth). Its centre can also be moved away from the normal central wavelength. This change and widening are due to a variety of factors.

These specific causes can be classified into two groups. There are two types of widening: broadening due to local conditions and broadening due to extended conditions. Broadening happens in local conditions without much effect from the output location, usually enough to maintain local thermodynamic equilibrium. When the light from an object is interfacing with our eyes, it does not just make one pattern of light. When the object’s part (or camera) crosses through different surfaces, it may start to display a change in spectrum at certain points. These patterns of Line Spectra are called broadening. It can also be caused by the mixing of radiation from many places that are far apart. 

A double line spectrum measures the intensity of light or other electromagnetic radiation. It can be used to determine the temperature of an object or the concentration of a chemical substance. A single line spectrum measures the intensity of light or other electromagnetic radiation, and it can be used to determine the temperature of an object or the concentration of a chemical substance. A double-line spectrum contains twice as much information as a single-line spectrum when it comes to spectra. A double-line spectrum reveals more details about what’s going on in an object than a single-line spectrum does.

Line Spectrum of Hydrogen 

The line Spectrum of Hydrogen ranges from atomic hydrogen to molecular hydrogen to ionised hydrogen. Hydrogen has been a part of mankind’s history since the beginning of time. The line emission spectrum of hydrogen is a major constituent of most planets and stars, and it is also one of the most abundant elements in the universe. According to the International Union of Pure and Applied Chemistry, there are three main types: atomic hydrogen (H), molecular hydrogen (H), and ionised hydrogen (H). Atomic Hydrogen exists as single atoms and molecules but not as ions. Molecular Hydrogen exists in various degrees of dissociation from H2 molecules, which is only possible at high temperatures or exposed to UV light.

Conclusion

The line spectra of the two elements are not identical because of the different number of electrons and atomic nuclei. The number of electrons determines the wavelengths, while the atomic nucleus determines the line width or spacing between these lines. In an otherwise continuous and uniform spectrum, a spectrum line is described as a dark or brilliant line arising from light absorption and emission in a limited frequency range relative to surrounding frequencies. These fingerprints can identify which materials are in stars and planets, who they’ve been with, and where to find them. They’re matched up to previously collected prints, making it a lot easier to track down residues that have been in our environment for a while and are now being discovered on various surfaces. 

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