Emission vs Continuous Spectrum
Spectrums are graphs of light. Emission spectrums and continuous spectrums are two out of the three types of spectrums. The other type is the absorption spectrum. The applications of spectrums are enormous. It can be used to measure the elements and bonds of a compound. It even can be used to measure the distance of distant stars and galaxies, and much more. Even the colors we see can be explained using the spectrum. Therefore, it is particularly beneficial to have a solid understanding in the theories and applications of emission and continuous spectrums. In this article, we are going to discuss what emission spectrum and continuous spectrum are, how they can be produced, the similarities between them, their applications and finally the differences between continuous spectrum and emission spectrum.
What is Continuous Spectrum?
To understand the continuous spectrum one must first understand the nature of electromagnetic waves. An electromagnetic wave is a wave that consists of an electric field and a magnetic field, which are perpendicular to each other. Electromagnetic waves are classified into several regions according to their energy. X-rays, ultraviolet, infrared, visible, radio waves are to name a few of them. Everything we see is due to the visible region of the electromagnetic spectrum. A spectrum is the plot of intensity versus energy of the electromagnetic rays. The energy can also be represented in wavelength or frequency. A continuous spectrum is a spectrum in which all the wavelengths of the selected region have intensities. The perfect white light is a continuous spectrum over the visible region. It must be noted that, in practice, it is virtually impossible to obtain a perfect continuous spectrum.
What is Emission Spectrum?
To understand the theory behind emission spectrum one must first understand the atomic structure. An atom consists of a nucleus, which is made of protons and neutrons, and electrons, which are orbiting around the nucleus. The orbit of an electron depends on the energy of the electron. Higher the energy of the electron farther away from the nucleus it would orbit. Using quantum theory it can be showed that electrons cannot just get any energy level. The energies the electron can have are discrete. When a sample of atoms is provided with a continuous spectrum over some region, the electrons in the atoms absorb specific amounts of energies. Since the energy of an electromagnetic wave is also quantized, it can be said that the electrons absorb photons with specific energies. After this incident, continuous spectrum is removed, then the electrons of these atoms will try to come to the ground level again. This will cause the photons in specific energies to be emitted. These photons create an emission spectrum, which has only bright lines corresponding to those photons.
What is the difference between emission spectrum and continuous spectrum?
• The continuous spectrum is a continuous bright region with all the wavelengths of the selected region present.
• An emission spectrum has only bright lines in a wide dark region corresponding to the photons absorbed and emitted by the electrons.