pass an electric current
91Earth exploration — Introduction the investigation of the surface of the Earth and of its interior. By the beginning of the 20th century most of the Earth s surface had been explored, at least superficially, except for the Arctic and Antarctic regions. Today the… …
92photography, technology of — Introduction equipment, techniques, and processes used in the production of photographs. The most widely used photographic process is the black and white negative–positive system (Figure 1 >). In the camera the lens projects an image of… …
93Force — For other uses, see Force (disambiguation). See also: Forcing (disambiguation) Forces are also described as a push or pull on an object. They can be due to phenomena such as gravity, magnetism, or anything that might cause a mass to accelerate …
94Nikola Tesla — Tesla, aged 37, 1893, photo by Sar …
95Electromagnet — An electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current. The magnetic field disappears when the current is turned off. Electromagnets are widely used as components of other electrical devices,… …
96Magnetic circuit — Magnetic Circuits Conventional Magnetic Circuits Magnetomotive force Magnetic flux Φ Magnetic reluctance Phasor Magnetic Circuits Complex reluctance Zμ …
97Microbial fuel cell — A microbial electrolysis cell A microbial fuel cell (MFC) or biological fuel cell is a bio electrochemical system that drives a current by mimicking bacterial interactions found in nature. Mediator less MFCs are a more recent development; due to… …
98chemical industry — Introduction complex of processes, operations, and organizations engaged in the manufacture of chemicals and their derivatives. Although the chemical industry may be described simply as the industry that uses chemistry and… …
99Fuel cell — For other uses, see Fuel cell (disambiguation). Demonstration model of a direct methanol fuel cell. The actual fuel cell stack is the layered cube shape in the center of the image A fuel cell is a device that converts the chemical energy from a… …
100Antenna (radio) — Whip antenna on car …
