How much electromagnetic energy is contained in each cubic meter near the Earth's surface if the intensity of sunlight under clear skies is 1000 W/m²? A)3.3 × 10−6 J B)3.3 J C)0.003 J D)10−4 J E)3.0 × 105 J

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Quizplus · Accepted Answer

The intensity of sunlight is 1000 W/m², which means that 1000 J of energy is incident on each square meter of surface area each second. The speed of light is 3 × 10⁸ m/s, so the energy density (energy per unit volume) is:$$u = \frac{1000 ext{ J/m}^2 ext{s}}{3 imes 10^8 ext{ m/s}} = 3.3 imes 10^{-6} ext{ J/m}^3$$

How Much Electromagnetic Energy Is Contained in Each Cubic Meter