Continuous spectrums and line spectrums?

Question

what is the source of a continuous spectrum? what is the source of a line spectrum? What kind of info does each give?

Answer 1

Continuous spectra are caused by so-called black body radiation, which is the radiation things give off because of their heat. By studying the wavelength-vs.-brightness curve of a continuous spectrum, you can determine how hot the object is.

Line spectra come in two types, each with a different cause. Bright-line spectra are caused by atoms (typically in a gas) emitting light as they move from a higher energy state to a lower energy state. Each type of atom has different energy levels at each state, so each type of atom emits bright-line spectra at a different set of wavelengths. By knowing which wavelengths belong to which elements, you can tell what the emitting gas is composed of.

Dark-line spectra occur when light from a continuous-spectrum emitter passes through a cloud of gas between us and the source. Atoms (and sometimes molecules) in the gas will absorb certain wavelengths and bump up to a higher energy state in the process. These are exactly the same wavelengths as the bright-line spectra. By knowing which wavelengths belong to which elements, you can determine the composition of the intervening gas.

Answer 2

A continuous spectrum is put out by a solid, warm object. (black body radiation.) A bright line spectrum is put out by a hot gas. A dark line spectrum (continuous with dark lines where the bright lines would normally be) is created by having a cold gas in front of a hot object. The object makes the continuous spectrum, and the gas absorbs the colours it would have put out had it been hot.

Answer 3

Continuous spectrums are ranges of wavelengths of light (or other em radiation for that matter) that do not have gaps between color values, such as created by using a prism to diffract the light. I'm not sure what kind of useful information could be garnered from this.

Line spectrums are the specific frequencies of light (or other em) that different elements produce either through absorbtion of emmission. The use of this is to determine the chemical makeup of whatever is producing the light.