# What do spectral lines show?

A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.

From spectral lines astronomers can determine not only the element, but the temperature and density of that element in the star. The spectral line also can tell us about any magnetic field of the star. The light from the stuff between the stars allows astronomers to study the interstellar medium (ISM).

Beside above, what does a star’s dark line spectrum reveal? All stars have darkline (absorption) spectra-bands of color crossed by dark lines where the color is diminished. What does a Star’s darkline spectra reveal? the star’s composition and temperature. Elements in the outer layers absorb some of the light radiating from within the star.

Accordingly, how do you identify a spectral line?

Emission lines are seen as coloured lines on a black background. Absorption lines are seen as black lines on a coloured background. The presence of spectral lines is explained by quantum mechanics in terms of the energy levels of atoms, ions and molecules.

What are spectral lines and how are they formed?

When electrons move from a higher energy level to a lower one, photons are emitted, and an emission line can be seen in the spectrum. Absorption lines are seen when electrons absorb photons and move to higher energy levels.

### Why are spectral lines important?

Spectral lines are often used to identify atoms and molecules. These “fingerprints” can be compared to the previously collected “fingerprints” of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible.

### How many spectral lines are there?

Answer: Total number of spectral lines = (n2−n1)(n2−n1−1)/2Here, n2=5 and n1=1Therefore, total number of spectral lines = (5−1)(5−1−1)/2=202=10i. e. total 10 lines i.e. 5→4,5→3,5→2,5→1,4→3,4→2,4→1,3→2,3→1,2→1 are possible in this case.

### What do absorption lines tell us?

As photons fly through the outermost layers of the stellar atmosphere, however, they may be absorbed by atoms or ions in those outer layers. The absorption lines produced by these outermost layers of the star tell us a lot about the chemical compositition, temperature, and other features of the star.

### Which element has the most spectral lines?

Mercury: the strongest line, at 546 nm, gives mercury a greenish color. Fig. 2. When heated in a electric discharge tube, each element produces a unique pattern of spectral `lines’.

### How many spectral lines does hydrogen have?

So, there are four lines in the visible spectrum of hydrogen. There are, of course, lots of other lines in hydrogen’s spectrum but they are all outside of our visible range so we cannot see them with our naked eye (and a diffraction grating).

### How are absorption lines formed?

The intensity depends on the density and temperature of the gas. An absorption line is produced when a photon of just the right energy is absorbed by an atom, kicking an electron to a higher energy orbit. Other photons moving through the gas with the wrong energy will pass right on by the atoms in the thin gas.

### What does each spectral line represent?

The observation of spectral lines is experimental evidence that proves that energy levels are discrete. Hence, one spectral line corresponds to one type of electron transition with corresponding transition energy given by the frequency of the spectral line.

### How do spectral lines identify elements?

When an atom absorbs energy, its electrons jump to higher energy levels. Each transition has a specific energy difference. This collection of transitions makes up an emission spectrum. These emission spectra are as distinctive to each element as fingerprints are to people.

### Why do different elements have different spectral lines?

Each element has a different atomic spectrum. The production of line spectra by the atoms of an element indicate that an atom can radiate only a certain amount of energy. This leads to the conclusion that bound electrons cannot have just any amount of energy but only a certain amount of energy.

### What causes spectral line broadening?

Thermal (doppler) broadening. It is due to the doppler shift caused by the motion, relative to the observer, of the atoms which emit light. Collisions among the excited atoms that induce the electronic transition and consequent emission of light.

### What is a star’s spectrum?

Spectra of Stars. A spectrum (the plural is spectra) is a graph of the amount of light something gives off (how bright the object is) at different wavelengths. In the spectra of stars, we frequently do not know the distances to the stars, so a star’s spectrum shows how bright it appears from Earth.

### What are absorption lines?

An absorption line will appear in a spectrum if an absorbing material is placed between a source and the observer. This material could be the outer layers of a star, a cloud of interstellar gas or a cloud of dust. Absorption lines are usually seen as dark lines, or lines of reduced intensity, on a continuous spectrum.

### What Colours of light are absorbed by hydrogen gas?

What colors of light are absorbed by hydrogen gas? Orange, light blue, bright blue, and indigo are absorbed by hydrogen gas.

### What is intensity of spectral lines?

The intensity of a spectral line at a given frequency is related to the net rate of absorption (or emission) at that frequency. The more intense the incident radiation, the greater the rate at which transitions are induced to the higher state and thus the stronger the absorbance of the sample.