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Amrutha T posted an Question
June 23, 2020 • 01:15 am 30 points
  • IIT JAM
  • Physics (PH)

What is the difference between pressure of radiation and pressure of diffuse radiation

what is the difference between pressure of radiation and pressure of diffuse radiation

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  • Isha lohan 1

    https://phys.libretexts.org/Bookshelves/Astronomy_and_Cosmology_TextMaps/Map%3A_Stellar_Atmospheres_(Tatum)/01%3A_Definitions_of_and_Relations_between_Quantities_used_in_Radiation_Theory/1.18%3A_Radiation_Pressure_(P)

  • Isha lohan 1

    In the above formula, you are right that u is same as energy density, P can be equal to U/3 or U/2 or U or 2U, depending upon circumstances, you can refer link attached for detailed information. I think in the givenexpression here, exact circumstances are not explained. I think so that due to diffuse radiation the expression takes the form of U/2. further chek link

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    Chandra prakash best-answer

    Radiation pressure : When an electromagnetic wave incidents and hits on the surface of the object,it will exert a force at its surface area and the pressure formed due to this is known as Radiation Pressure. This results from the momentum carried by that radiation. Radiation Pressure = (dp/dt) / A = φ / C = Energy flux / Speed of Light , (OR) = Intensity of Radiation / Speed of Light NOTE: Radiation pressure is doubled ,if the radiation is reflected rather than absorbed.

    eduncle-logo-app

    sir, i actually ask whether u/2=energy density/3 or not. is this energy density and u are not same??

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    Dhairya sharma

    i think both should be same ....but let me check once

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    Amrutha t

    mam, they given that pressure of diffuse radiation=p=u/2=energy density/3.actually both u and energy dencity are same. then why they given so

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    Dhairya sharma

    Diffusion pressure : It is a hypothetical term coined by Meyer (1938) to denote the potential ability of the molecules or ions of any substance to diffuse from an area of their higher concentration to that of their lower concentration

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    Dhairya sharma Best Answer

    Radiation pressure is the mechanical pressure exerted upon any surface due to the exchange of momentum between the object and the electromagnetic field. This includes the momentum of light or electromagnetic radiation of any wavelength which is absorbed, reflected, or otherwise emitted by matter on any scale

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