Same as law of conservation of energy. Fluid: material that flows, i.e. liquids, gases, and plasmas. Focal length: distance from the focal point to the center of a lens or vertex of a mirror. Focal point: location at which rays parallel to the optical axis of an ideal mirror or lens converge to a point. Forbidden gap: energy values that electrons in a semiconductor or insulator may not have. Force: agent that results in accelerating or deforming an object. Frame of reference: coordinate system used to define motion.
Tuberculosis skin test facts. 1  The tuberculosis skin test is also known as the tuberculin test or PPD test.  The PPD test is used to determine if someone has developed an immune response to the bacterium that causes tuberculosis (TB).
TB Tuberculin Test. A tuberculosis skin test (also known as the tuberculin skin test or PPD skin test) is often used to identify if someone has been infected with TB. New tests, such as QuantiFERONÂ®-TB Gold In-Tube Test, identify the infection through blood testing.