F scale

The terms F scale and F number may refer to several things:The F-scale is a personality test that attempts to quantify authoritarian tendencies.The Fujita scale, sometimes abbreviated "F scale", rates a tornado's intensity by its impact on structures and vegetation. Often, when a tornado is rated on this scale, it is said to have been given an "F number".In photography, the f-number refers to the relative aperture of a lens.The F scale is a 2.781 in (70.62 mm) gauge track used with  model trains.In chemistry, the F number is a number that can be calculated for polycyclic aromatic hydrocarbons from their structure. It is used in liquid chromatography.
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For F-scale as the Fujita scale of tornado intensity, see Fujita scale The F-scale is a personality test (psychometric assessment) that attempts to quantify authoritarian tendencies. The F-scale was designed on the basis of Theodor Adorno's theory of authoritarian personality. The "F" stands for "fascism."
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"F-scale" redirects here. For other uses, see F scale. The Fujita scale (F-Scale), or Fujita-Pearson scale, is a scale for rating tornado intensity, based on the damage tornadoes inflict on human-built structures and vegetation. The official Fujita scale category is determined by meteorologists (and engineers) after a ground and/or aerial damage survey; and depending on the circumstances, ground-swirl patterns (cycloidal marks), radar tracking, eyewitness testimonies, media reports and damage imagery, as well as photogrammetry/videogrammetry if video is available.
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See Fujita Scale

A scale of wind damage intensity in which wind speeds are inferred from an analysis of wind damage: F0 (weak): 40- 72 mph, light damage.
F1 (weak): 73-112 mph, moderate damage. F2 (strong): 113-157 mph, considerable damage. F3 (strong): 158-206 mph, severe damage. F4 (violent): 207-260 mph, devastating damage. F5 (violent): 261-318 mph, (rare) incredible damage.
All tornadoes , and most other severe local windstorms, are assigned a single number from this scale according to the most intense damage caused by the storm.