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Gravity is computed on the ellipsoid surface using the International Gravity Formula. For studies of subsurface structure, the free-air anomaly is further adjusted by a correction for the mass below the measurement point and above the reference of mean sea level or a local datum elevation. [3] This defines the Bouguer anomaly.
The Prentice position. The Prentice position is an orientation of a prism, used in optics, optometry and ophthalmology. [1] In this position, named after the optician Charles F. Prentice, the prism is oriented such that light enters it at an angle of 90° to the first surface, so that the beam does not refract at that surface.
A burning apparatus consisting of two biconvex lens. A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction.A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis.
The Eötvös effect is the change in measured Earth's gravity caused by the change in centrifugal acceleration resulting from eastbound or westbound velocity.When moving eastbound, the object's angular velocity is increased (in addition to Earth's rotation), and thus the centrifugal force also increases, causing a perceived reduction in gravitational force.
It is named for its creator, Bernard Lewis Welch, and is an adaptation of Student's t-test, [1] and is more reliable when the two samples have unequal variances and possibly unequal sample sizes. [ 2 ] [ 3 ] These tests are often referred to as "unpaired" or "independent samples" t -tests, as they are typically applied when the statistical ...
Depending on the exact shape of the hole, the relative thickness of the sheet with respect to the size of the hole and the size of the cavity, this formula can have limitations. More sophisticated formulae can still be derived analytically, with similar physical explanations (although some differences matter). [ 6 ]
The van der Pauw Method is a technique commonly used to measure the resistivity and the Hall coefficient of a sample. Its strength lies in its ability to accurately measure the properties of a sample of any arbitrary shape, as long as the sample is approximately two-dimensional (i.e. it is much thinner than it is wide), solid (no holes), and the electrodes are placed on its perimeter.
A corner reflector for radar testing. A corner reflector is a retroreflector consisting of three mutually perpendicular, intersecting flat reflective surfaces. It reflects waves incident from any direction directly towards the source, but translated.