An electromagnetic wave strikes a 2.00-cm2 section of wall perpendicularly. The rms value of the wave’s magnetic field is determined to be 5

Question

An electromagnetic wave strikes a 2.00-cm2 section of wall perpendicularly. The rms value of the wave’s magnetic field is determined to be 5.00 10-4 T. How long does it take for the wave to deliver 1600 J of energy to the wall?

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Khang Minh 4 years 2021-07-27T12:27:27+00:00 1 Answers 17 views 0

Answers ( )

  1. Sapo1
    0
    2021-07-27T12:29:15+00:00
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    Answer:t=0.134 s

    Explanation:

    Given

    Area of wall over which wave strikes A=2\ cm^2

    Intensity of Electromagnet wave is I=\frac{c}{\mu _o}B_{rms}^2

    where [/tex]c[/tex]=speed of light

    \mu _o=Permeability of free space

    B_{rms}=RMS value of magnetic field

    I=\frac{3\times 10^8}{4\pi \times 10^{-7}}\times (5\times 10^{-4})^2

    I=5.96\times 10^7\ W/m^2-s

    Average power is

    P=I\cdot A

    P=5.96\times 10^7\times 2\times 10^{-4}

    P=11.92\times 10^{3}

    P=11.92\ kW

    time taken t=\frac{Energy}{Power}

    t=\frac{1600}{11.92\times 10^3}

    t=0.134\ s

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