When atom absorbed quantum energy, it move to an excited state opposing it ground state. When this atom loose or emitted the absorb energy or light, it will return to ground state. In this tutorial we going to used glass for illustration, when a glass is heated in a flame, it give a yellow flame, the yellow flame is as a result of excited sodium atom in the glass that is going back to their respective ground state. Also the familiar red light of neon signs is as a result of neon atoms that is been excited by the influence of electrical discharged. Spectroscope is one of the instrument use to view the excited state of an atom, so when the excited atom are view through the spectroscope, slit image is observed, the observed image is along the instrument scale appear as a series of coloured lines. The different coloured observed suite a light of different wavelengths, the series of line observed is called line spectrum. The line spectrum of various element is the fixture of that element, and the spectrum may use to identify each of the element present. Hydrogen element has the simplest spectrum, and that is the element we shall work on in the course our illustration.
Above picture illustrate the part of hydrogen spectrum light that appear visible to eyes. It should be bear in mind that line with short wavelengths possess low progressive intensities. Successive wavelength line come closer and closer to each other, and finally result to continuum, the region of continuum appear as faint light as it shown on the above picture. In year 1885, J.J. Balmer predict an equation, he predict that visible line of hydrogen atom could be represent in the following equation; ṽ = = R (1/n12 - 1/n22).
ṽ =represent inverse of wavelength,
n1 = has value of 2
n2 = is the integer, the value continue, 3, 4, 5, 6, …………… till infinity.
R= it known as Rydberg constant, the value is 109,677.581cm - 1