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half-life period (T1/2)
period f

Half life. The time required for a measurement with exponential decay to fall to half its value. His unit is the second. The same term applies to exponential growth. If the half-life of a substance is 5 seconds, for example, it will decay to half its activity in 5 seconds, to a quarter of its activity in 10, and to an eighth of its activity in 15. . and so on .
For example, y in the drawing may be the number of radioactive parent nuclei in a sample, or the voltage between the ends of an inductor after connecting the circuit, or the charging current in a capacitor.


half-wave rectification
Redressing simple alternance

Half-wave calendar. See rectification.


heat. heat
chaleur f

heat. A form of energy. It is the internal energy of matter, which is represented by the movement of molecules. It is also a common name for the transfer of energy. Thus, when “we charge a container containing water, there is a transfer of energy from fuel or electricity to the movement of particles that increases conduction, thermal, and kinetic model. See note. Note that heat is a form of energy, while temperature is its level, or degree.” The hotness.


heat capacity
Capacity and calorific value

Heat capacity. The ability of a material to store heat. The specific heat capacity of a substance is the amount of heat, measured in joules, required to raise the temperature of one kilogram of the substance by one degree Celsius.

W = mc0

See also latent heat.


hertz
hertz m

Hertz is a frequency of one cycle per second.


holography
holographie f

Stereoscopic imaging. Technology of recording a three-dimensional image of the body using laser light. When the film is developed, different views of the body appear from different angles. Modern holograms can be seen in normal light. It shows live 3D images of large objects in full color. Stereoscopic television is now being developed.


Hooke's law
loi f de Hooke

Hooke's law. When an elastic material, such as a spring, is stretched,
Its extension is directly proportional to the applied force, provided that the elastic limit is not exceeded. Thus, a spring stretched from 101 cm to 101 cm with a force of 20 Newtons (N) extends to 102 cm with a force of 40 Newtons, to 103 cm with a force of 600 Newtons, and so on. The spring returns to its original position when the force exerted on it is removed.
All materials are flexible to a certain extent. See also elasticity.


hydraulic machines
machines fpl hydrauliques

Hydraulic machines. People use machines to transfer energy from input to output in a way that allows for a change in force and/or direction. In hydraulic machines, pressure in a fluid (which cannot be compressed) is used to transfer energy. Below is a simple drawing of a liquid ballast.


hydraulic press
Presse hydraulique

Hydraulic press. A hydraulic piston or hydraulic jack uses a small force over a small area to exert a large force over a large area.

(Force)/(Area) = F1/A1 = F2/A1 = Pressure
Hydraulic press


hydroelectricity
hydroelectricity f

Water electricity. Using the energy of falling water, perhaps from behind the Dam Dam, to produce electrical power. These power plants may be expensive to build, but they are inexpensive to operate, and they allow large-scale storage of electricity. In the pumped storage system, a portion of the network capacity is used during the night to return the falling water beyond the dam, so that a greater amount of capacity is available for use during times of peak electricity demand. See also generator.


hydrometer
hydrometre m

Hydrometer. A device used to measure the relative density of a liquid in order to check the condition of a car battery, milk, and alcoholic beverages. The higher the specific density of the liquid, the greater the buoyancy (buoyancy) of the scale. The readings on the scale column give the relative density. See also Archimedes' principle.

A long, narrow glass tube
Grading at unequal distances
Sealing wax.
bullets.
Hydrometer