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The mass-to-charge ratio ( m / Q) is a physical quantity relating the mass (quantity of matter) and the electric charge of a given particle, expressed in units of kilograms per coulomb (kg/C). It is most widely used in the electrodynamics of charged particles, e.g. in electron optics and ion optics .
Electrical device. Electric (al) devices are devices that functionally rely on electric energy ( AC or DC) to operate their core parts ( electric motors, transformers, lighting, rechargeable batteries, control electronics ). They can be contrasted with traditional mechanical devices which depend on different power sources like fuels or human ...
In physics, an electronvolt (symbol eV, also written electron-volt and electron volt) is the measure of an amount of kinetic energy gained by a single electron accelerating from rest through an electric potential difference of one volt in vacuum. When used as a unit of energy, the numerical value of 1 eV in joules (symbol J) is equivalent to ...
Time. Watch, a time measurement device. In the past, a common time measuring instrument was the sundial. Today, the usual measuring instruments for time are clocks and watches. For highly accurate measurement of time an atomic clock is used. Stopwatches are also used to measure time in some sports.
History. Historically, the definition of a scientific instrument has varied, based on usage, laws, and historical time period. Before the mid-nineteenth century such tools were referred to as "natural philosophical" or "philosophical" apparatus and instruments, and older tools from antiquity to the Middle Ages (such as the astrolabe and pendulum clock) defy a more modern definition of "a tool ...
In chemistry, electrophoresis is the motion of charged dispersed particles or dissolved charged molecules relative to a fluid under the influence of a spatially uniform electric field. As a rule, these are zwitterions. Electrophoresis of positively charged particles or molecules ( cations) is sometimes called cataphoresis, while electrophoresis ...
Melde's experiment. A model of Melde's experiment: an electric vibrator connected to a cable drives a pulley that suspends a mass that causes tension in the cable. Melde's experiment is a scientific experiment carried out in 1859 by the German physicist Franz Melde on the standing waves produced in a tense cable originally set oscillating by a ...
Electrometer. Kolbe electrometer, precision form of gold-leaf instrument. This has a light pivoted aluminum vane hanging next to a vertical metal plate. When charged the vane is repelled by the plate and hangs at an angle. An electrometer is an electrical instrument for measuring electric charge or electrical potential difference. [1]