QPage 339: Q9: HC Verma: Concepts of Physics - Volume 2 Electromagnetic Waves Page 339: Q9 Solution: The intensity of the sunlight reaching Earth is . Assume this…

Question

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The intensity of the sunlight reaching Earth is

1380 \text{ W m}^{-2}

. Assume this light to be a plane, monochromatic wave. Find the amplitudes of electric and magnetic fields in this wave.

Accepted Answer

**Answer:**

E_0 = 1.02 \times 10^3 \, \text{V/m}

,

B_0 = 3.4 \times 10^{-6} \, \text{T}

. **Step-by-Step Explanation:** Given: Intensity

I = 1380 \, \text{W/m}^2

.

E_0 = \sqrt{\frac{2I}{\epsilon_0 c}} = \sqrt{\frac{2 \times 1380}{8.85 \times 10^{-12} \times 3 \times 10^8}} = \sqrt{\frac{2760}{2.655 \times 10^{-3}}} = \sqrt{1.04 \times 10^6} = 1.02 \times 10^3 \, \text{V/m}

.

B_0 = \frac{E_0}{c} = \frac{1.02 \times 10^3}{3 \times 10^8} = 3.4 \times 10^{-6} \, \text{T}

[citation:4].

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