Intensity of sunlight is observed as

Question:

Intensity of sunlight is observed as $0.092 \mathrm{Wm}^{-2}$ at a point in free space. What will be the peak value of magnetic field at that point ?

$\left(\varepsilon_{0}=8.85 \times 10^{-12} \mathrm{C}^{2} \mathrm{~N}^{-1} \mathrm{~m}^{-2}\right)$

1. $2.77 \times 10^{-8} \mathrm{~T}$

2. $1.96 \times 10^{-8} \mathrm{~T}$

3. $8.31 \mathrm{~T}$

4. $5.88 \mathrm{~T}$

Correct Option: 1

Solution:

$\mathrm{I}_{\text {avg }}=\frac{\mathrm{B}_{0}^{2} \mathrm{C}}{2 \mu_{0}} \& \frac{1}{\mu_{0}}=\epsilon_{0} \mathrm{C}^{2}$

$I=\frac{B_{0}^{2}}{2} \in_{0} C^{3}$

$\mathrm{B}_{0}=\sqrt{\frac{2 \mathrm{I}}{\epsilon_{0} \mathrm{C}^{3}}}$

$\mathrm{B}_{0}=2.77 \times 10^{-8} \mathrm{~T}$