Since 1˜ν=λ in units of cm, this converts to 364 nm as the shortest wavelength possible for the Balmer series.

Absorption lines are usually seen as dark lines, or lines of reduced intensity, on a continuous spectrum. This is seen in the spectra of stars, where gas (mostly hydrogen) in the outer layers of the star absorbs some of the light from the underlying thermal blackbody spectrum.

Formulas for the number of spectral lines

1. When electrons de-excite from higher energy level (n2) to lower energy level (n1) in atomic sample, then number of spectral line observed in the spectrum is.
2. When electron de-excites from higher energy level (n2) to lower energy level (n1) in isolated atom, then number of spectral line observed in the spectrum is.

3 lines

Do someof the lines on the two spectra match up? Yes, 4 of them line up.

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 width of the line can tell us how fast the material is moving. We can learn about winds in stars from this.

An absorption spectrum is produced when a continuum passes through “cooler” gas. Photons of the appropriate energies are absorbed by the atoms in the gas. The atmospheres of stars act as a cooler blanket around the hotter interior of a star so that typical stellar spectra are absorption spectra.

Essentially, astronomers determine the age of stars by observing their spectrum, luminosity and motion through space. They use this information to get a star’s profile, and then they compare the star to models that show what stars should look like at various points of their evolution.

The spectra of most stars are of the dark line, or absorption type. How is the Doppler Effect used? Doppler effect is used to determine whether a star or other body in space is moving away from or toward Earth.

Blue