thermionic emission (thurÂ´mÄ«onik imishÂ´Én), n the release of electrons when a material is heated (e.g., electron emission when the tungsten cathode filament of a radiographic tube is heated to incandescence by means of its low-voltage heating circuit).
The number of cycles per second (Hertz) (abbreviated as, hz) of anything that oscillates is called the frequency. The electricity of an AC wall outlet is said to have a frequency of 60 Hertz as it cycles negative then positive 60 times each second. Sound is an oscillating wave, but it has a broad range of frequencies. A low frequency sound (say, 50 hz) might sound like a low rumble, while a high frequency sound (say 12,000 hz), might sound more like a sizzle. A person with normal hearing can hear all the way up to about 20,000 hz.
The relative frequency histogram gives the fraction of times the data occur in the particular group or interval. Relative frequency distribution of a class is the ratio of the frequency of the class to the total number of the items.A uniform distribution often means that the number of classes is too small, each class has about the same number of elements. It may describe a distribution which has several peaks.he relative frequency table is a compact numerical way to present how the data is distributed. If the frequencies are plotted as columns, the resulting plot is called a histogram. A frequency distribution shows the number of items in each of several overlapping classes.