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Radiation pressure or force on a surface from the intensity

This type of question, asked 5 times: 28 Jul 2022, 30 Jan 2023, 27 Jan 2024, 8 Apr 2024, 3 Apr 2025. All 5 questions below, oldest first.

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  1. Question 1

    28 Jul 2022

    105
    Sun light falls normally on a surface of area 36 cm236{\text{ }cm}^{2} and exerts an average force of 7.2×10−9 N7.2 \times10^{- 9}\text{ }N within a time period of 20 minutes. Considering a case of complete absorption, the energy flux of incident light is

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  2. Question 2

    30 Jan 2023

    25
    A point source of light is placed at the centre of curvature of a hemispherical surface. The source emits a power of 24 W24\text{ }W. The radius of curvature of hemisphere is 10 cm10\text{ }cm and the inner surface is completely reflecting. The force on the hemisphere due to the light falling on it is____ 10−8 N10^{- 8}\text{ }N
  3. Question 3

    27 Jan 2024

    107
    An object is placed in a medium of refractive index 3. An electromagnetic wave of intensity 6×108 W/m26 \times10^{8}\text{ }W/m^{2} falls normally on the object and it is absorbed completely. The radiation pressure on the object would be (speed of light in free space =3×108 m/s= 3 \times10^{8}\text{ }m/s ):

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  4. Question 4

    8 Apr 2024

    2
    Average force exerted on a non-reflecting surface at normal incidence is 2.4×10−4 N2.4 \times10^{- 4}\text{ }N. If 360 W/cm2360\text{ }W/cm^{2} is the light energy flux during span of 1 hour 30 minutes. Then the area of the surface is:

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  5. Question 5

    3 Apr 2025

    4
    The radiation pressure exerted by a 450 W light source on a perfectly reflecting surface placed at 2 m away from it, is :

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