أكاديميا - كولنز - معاجم الجيب العلمية - الفيزياء - انكليزي - فرنسي - عربي الحرف ١_ l

Academia - Collins - Pocket Scientific Dictionaries - Physics - English - French - Arabic Letter 1_ L


laser
laser m

Laser. Light Amplification by Stimulated Emission of Radiation. The laser is a very effective light source.

Energy is absorbed by the atoms of the material used, and these atoms release energy in the form of photons. All photons travel in one direction in a continuum with the same frequency. Therefore, the exiting beam is strong, parallel, phased, and monochromatic.

Lasers are used in holography, holography, fiber optics, electronic engineering, science and industry. It is also useful in teaching the properties of light.

latch
bascule f

Retaj. A circuit that remains connected even when the original signal is cut off. This feedback is useful, for example, in burglar alarm systems where it is necessary to keep the alarm ringing. In this case, the circuit remains closed.


latent heat
Change the latency

Latent heat. This expression means “hidden” heat, which is the energy related to a change of state. If one adds heat at a constant rate to a solid sample, the temperature/time graph is as shown in (a) below. As for the liquid that loses heat at a constant rate, its temperature decreases as shown in (b) below:
In both cases, the temperature remains constant while the change is taking place, there is a transfer of energy to the state. With or from particles. The amount of energy transferred during a change of state depends on the quality and state of the substance. See - specific la tent heat.


lateral inversion
Inversion f laterale

Side reversal. The apparent flip of the image from left to right behind the mirror. This phenomenon results from the laws of reflection.


law
loi f

Law . A saying in physics that is always true in the cases it defines. It is a theory whose proof appears to be beyond any doubt. The reality is that no one can prove a theory forever, but perhaps it is only possible to refute the theory.

Newton's law of gravity has held up for two hundred years. Then came the concepts of relativity, which meant the necessity of changing that law. While Newton's law remains true on the local scale, it is in fact only a special case in Einstein's law of gravity. Even the latter may need to change in the future.


LDR
photoresistance f

Light-dependent resistor A light-conducting cell, or in other words a resistor that conducts electricity better when light falls on it because its resistance is reduced. Cadmium sulfide is usually used as a semiconductor, as its resistance changes from several megaohms in the dark to a few kiloohms in the light.
Abbreviation for light dependent resistor.

LED
photodiode f

Dual light source. A binary with a .p.n connection, usually made of gallium arsenide phosphide. The combination of holes and electrons releases energy in the form of light. The connection is close to the surface so that the emitting light can be seen. This diode is used in electronic displays. No light is emitted under reverse bias.


left hand motor rule
Règle f de la main gauche

Left hand rule. A method that helps the user know the direction of action of the motor effect: Extend the three fingers of the left hand, the thumb, index finger, and middle, so that they are perpendicular to each other. The directions of movement will then show you the force F on the conductor, the magnetic field B, and the current I.