Answer
given,
Power of bulb,P = 100 W
distance from bulb, r = 2.5 m
Intensity of bulb,
[tex]I = \dfrac{P}{A}[/tex]
P is the power of bulb
A is the area
[tex]I = \dfrac{P}{4\pi r^2}[/tex]
[tex]I = \dfrac{100}{4\pi\times 2.5^2}[/tex]
I = 1.274 W/m²
The relation between intensity I and E_max
[tex]I = \dfrac{E_{max}^2}{2\mu_0 c}[/tex]
where c is the speed of light
μ₀ = 4 π x 10⁻⁷
[tex]E_{max}=\sqrt{I(2\mu_0 c)}[/tex]
[tex]E_{max}=\sqrt{1.274\times (2\times 4\pi \times 10^{-7}\times 3 \times 10^8)}[/tex]
E_{max} = 30.99 V/m
now, maximum magnetic field
[tex]B_{max}=\dfrac{E_{max}}{c}[/tex]
[tex]B_{max}=\dfrac{30.99}{3\times 10^8}[/tex]
[tex]B_{max}= 1.033 x 10⁻⁷\ T[/tex]
