Conservation of Energy. Conservation of energy. In physics, the law of conservation of energy states that the total energy of an isolated system cannot change—it is said to be conserved over time. Energy can be neither created nor destroyed, but can change form, for instance chemical energy can be converted to kinetic energy in the explosion of a stick of dynamite. A consequence of the law of conservation of energy is that a perpetual motion machine of the first kind cannot exist. That is to say, no system without an external energy supply can deliver an unlimited amount of energy to its surroundings.[2] History[edit] Gottfried Leibniz Ancient philosophers as far back as Thales of Miletus c.~550 BCE had inklings of the conservation of some underlying substance of which everything is made.
In 1638, Galileo published his analysis of several situations—including the celebrated "interrupted pendulum"—which can be described (in modern language) as conservatively converting potential energy to kinetic energy and back again. . , or equivalently, Symbols. Forms of Energy. Forms of Energy. Energy Forms. Sankey Diagram. GCSE Bitesize: Efficiency. Energy Efficiency. What's Energy Efficiency? Resistor. Resistor. Ohm. Ohm's law. V, I, and R, the parameters of Ohm's law. where I is the current through the conductor in units of amperes, V is the potential difference measured across the conductor in units of volts, and R is the resistance of the conductor in units of ohms. More specifically, Ohm's law states that the R in this relation is constant, independent of the current.[3] The law was named after the German physicist Georg Ohm, who, in a treatise published in 1827, described measurements of applied voltage and current through simple electrical circuits containing various lengths of wire.
He presented a slightly more complex equation than the one above (see History section below) to explain his experimental results. The above equation is the modern form of Ohm's law. In physics, the term Ohm's law is also used to refer to various generalizations of the law originally formulated by Ohm. History Ohm's law was probably the most important of the early quantitative descriptions of the physics of electricity. Scope . Current. High Voltage.
Voltmeter.