Вы знали, что с помощь света Оль ‘notice the за! 46 reflective because reflected a _ light transfers twice the momentum ы of absorbed light Эта концепция даже используетс; для приведения в движение ко

Вы знали, что с помощь света
Оль ‘notice the за! 46 reflective because reflected
a _ light transfers twice the momentum
ы of absorbed light
Эта концепция даже используетс;
для приведения в движение
космических аппаратов
Поэтому, если у меня есть
достаточно СИЛЬНЫИ лазер И
чувствительный выключатель,
то в теории я могу выключить
свет, не вставая с кровати
Radiation pressure can be viewed as a consequence of the conservation of momentum
Well calculated on the basis of electromagnetic theory or from the combined momenta of a
stream of photons, giving identical results as is shown below.
Radiation pressure from momentum of an electromagnetic wave {cui |
Main article: Poynting vector
According to Maxwell's theory of electromagnetism, an electromagnetic wave carries
momentum, which will be transferred to an opaque surface it strikes.
The energy flux (irradiance) of a plane wave is calculated using the Poynting vector
$ = E x H, whose magnitude we denote by $. $ divided by the speed of light is the
density of the linear momentum per unit area (pressure) of the electromagnetic field. So,
dimensionally, the Poynting vector is S=22wet="ate of dona work which is the speed of
light, c=Ax/At, times pressure, AF/area. That pressure is experienced as radiation pressure
where P is pressure (usually in Pascals), Г, is the incident irradiance (usually in Wim?) and
If the surface is planar at an angle а to the incident wave, the intensity across the surface
will be geometrically reduced by the cosine of that angle and the component of the radiation
force against the surface will also be reduced by the cosine of a, resulting in a pressure:
surface, as given above. The component of that force tangent to the surface is not called
Bp света Ha поверхность тела 35
the reflected We hither contripute О Maton pressure In eesse el a perfect
reflector, this pressure will be identical to the pressure caused by the incident wave:
Poet = Розаны + Раши = 22
Рога partially reflective surface, the second term must be multiplied by the reflectivity (also
known as reflection coefficient of intensity), so that the increase is less than double. For a