Intensity of sunlight is observed as 0.092 Wm$-$2 at a point in free space. What will be the peak value of magnetic field at the point?
(${\varepsilon _0} = 8.85 \times {10^{ - 12}}{C^2}{N^{ - 1}}{m^{ - 2}}$)
Solution
${I \over C} = {1 \over 2}{\varepsilon _0}.E_0^2$<br><br>$\Rightarrow {E_0} = \sqrt {{{2I} \over {C{\varepsilon _0}}}}$<br><br>${{{E_0}} \over {{B_0}}} = C \Rightarrow {B_0} = {{{E_0}} \over C}$<br><br>$$ \Rightarrow {B_0} = \sqrt {{{2I} \over {{\varepsilon _0}{C^3}}}} = \sqrt {{{2 \times 0.092} \over {8.85 \times {{10}^{ - 12}} \times 27 \times {{10}^{ + 24}}}}} $$<br><br>$= 2.77 \times {10^{ - 8}}$ T
About this question
Subject: Physics · Chapter: Electromagnetic Waves · Topic: Properties of EM Waves
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