Description: The octopus is a mollusk in the class Cephalopoda. Cephalopoda means âhead footâ in Greek, and in this class of organisms the head and foot are merged. A ring of eight equally-long arms surround the head. The arms are covered on the underside with suction cups that are very sensitive to touch and taste.
Light fixture. A light fixture (US English), light fitting (UK English), or luminaire is an electrical device used to create artificial light by use of an electric lamp. All light fixtures have a fixture body and a light socket to hold the lamp and allow for its replacement.
Cognitive Psychology: Attention Â· Decision making Â· Learning Â· Judgement Â· Memory Â· Motivation Â· Perception Â· Reasoning Â· Thinking-Cognitive processes Cognition-Outline Index. Luminance (also called luminosity) is a photometric measure of the density of luminous intensity in a given direction. It describes the amount of light that passes through or is emitted from a particular area, and falls within a given solid angle. The SI unit for luminosity is candela per square metre (cd/m 2). Luminance is often used to characterize emission or reflection from flat, diffuse surfaces.