The magnitude of the Poynting vector of a planar electromagnetic wave has an average value of 0.939 W/m^2 . The wave is incident upon a rect

Question

The magnitude of the Poynting vector of a planar electromagnetic wave has an average value of 0.939 W/m^2 . The wave is incident upon a rectangular area, 1.5 m by 2.0 m, at right angles. How much total electromagnetic energy falls on the area during 1.0 minute?

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Philomena 4 years 2021-08-29T13:34:44+00:00 1 Answers 101 views 0

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  1. RobertKer
    -1
    2021-08-29T13:35:56+00:00
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    Answer:

    47 mW

    Explanation:

    The average value of the Poynting vector, S = 0.939 W/m² = Intensity of wave, I

    S = I S

    Also, I = P/A where P = Et, P = power of electromagnetic wave, E = energy of electromagnetic wave in time t and t = time = 1 min = 60 s and A = area = lb since the electromagnetic waves falls on area equal to that of a rectangle.

    So, S = Et/A

    E = SA/t

    = Slb/t

    = 0.939 W/m² × 1.5 m × 2.0 m/60 s

    = 2.817 W/60 s

    = 0.047 W

    = 47 mW

    So, 47 mW of electromagnetic energy falls on the area in 1.0 minute.

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