أكاديميا - كولنز - معاجم الجيب العلمية - الفيزياء - انكليزي - فرنسي - عربي الحرف ٣_ t

Academia - Collins - Pocket Scientific Dictionaries - Physics - English - French - Arabic Letter 3_ T


time-base
base f de temps

Time base. A cathode ray diode, like a television, has a dot that moves across the screen from left to right. It is important that the bounce time, that is, the time for the point to return to the left, is very short. The speed at which the dot crosses the screen is controlled by a time rule.


torque(T)
couple f

Torque. The effect of rotation (or moment) exerted by a force on a body. In (a) below, the force F acts through the center of mass of the body. The body is free to move, so it accelerates in that direction without rotation. In (b) the force does not act through C, so the body tends to rotate around C. In (c) F acts through C, but the body is held at a certain point. In this case also there is torque.
Torque (or torque) is the product of force multiplied by its perpendicular distance from the point of rotation.
The unit is newton-meter (Nm). See the chart below.

T = Fs

total internal reflection
Total internal reflexion

Total internal reflection. Light passing through the glass bends into the air away from the regulator, as in Figure (A) below. Thus, there is a stage (b) in which the light leaves the glass at an angle of 90°. Then the angle of incidence is called the critical angle.

n = 1/sin c

(See refractive index). If it is greater than c, all the light is reflected, as in figure (c).
This is called total internal reflection, and it occurs when radiation meets the surface of the medium (less dense) at an angle greater than the critical angle.
See also prism binoculars and periscope.


tracer
marqueur m

Tracing element. A small amount of a radioactive isotope is used instead of the normal amount to give scientists valuable information. River pollution, sand movements in estuaries, brain scans, and bearing wear can be checked using small amounts of a radioactive tracer.