Ström

Strøm is a Norwegian term meaning current or flow. It is used to describe the movement of liquids, gases, or electric charges, and appears in scientific, engineering, and everyday language. The word is cognate with the Danish strøm and the Swedish ström, and derives from Old Norse straumr, meaning stream or current.

In electricity, elektrisk strøm refers to the rate at which electric charge passes a point. It is measured in amperes (A). Conventional current is defined as the flow of positive charge from higher to lower potential. Ohm's law relates current to voltage and resistance: I = V/R. Electric power is P = VI, with P = I^2R = V^2/R for a resistor. Direct current (DC) maintains a constant direction, while alternating current (AC) reverses direction periodically. Electrical circuits require conductors and protective devices to manage current safely.

In fluid dynamics, strøm denotes the flow of a liquid or gas. The key quantity is the volumetric flow rate Q, measured in cubic meters per second (m3/s) or liters per minute. For a uniform cross-section, Q = Av, where A is area and v is velocity. Flow can be laminar or turbulent, characterized by the Reynolds number. Flow is measured with various devices such as flow meters, venturi tubes, or rotameters.

Other uses include havstrømmer (ocean currents) and luftstrømmer (air currents) in meteorology and oceanography. The term also appears as a surname and in place names in Norwegian-speaking regions.