Account for the production of emission and absorption spectra and compare these with a continuous black body spectrum
- Continuous Spectrum: A spectrum in which all wavelengths are present.
- Since black bodies emit radiation of all frequencies, it is a continuous spectrum.
- Emission Spectrum: Spectrum produced by hot, incandescent gases at low density.
- Emission spectra have the appearance of a largely black rectangles with distinct coloured lines/bands.
- Emission spectra are produced when electrons of atoms drop down to a lower energy level, after first being excited to a higher level, and release photons of a particular frequency
- Molecules tend to emit band spectra.
- Absorption Spectrum: Spectrum produced by a cool, non-luminous gas being placed in front of a continuous spectrum source.
- Absorption spectra have the appearance of continuous spectra with discrete dark lines.
- An absorption spectra of an element is the negative of the emission spectra for the same element.
Extract from Physics Stage 6 Syllabus © 2017 NSW Education Standards Authority (NESA)