Question

On a sunny summer day, the intensity of sunlight at the earth's surface is about 1000 W/m2. What are the peak electric and magnetic fields in this sunlight?

Answer 1

Answer:

peak value of magnetic field is

$B_o = 2.9 \times 10^{-6} T$

peak value of electric field is

$E_o = 868 N/C$

Explanation:

As we know that the intensity of electromagnetic waves is given by the formula

$I = \epsilon_0 E_{rms}^2 c$

here we have

$I = 1000 W/m^2$

$\epsilon_0 = 8.85 \times 10^{-12}$

$c = 3\times 10^8$

now we have

$1000 = (8.85 \times 10^{-12})E_{rms}^2(3 \times 10^8)$

$E_{rms} = 614 N/C$

now peak value of electric field is given as

$E_o = \sqrt2 E_{rms}$

So the peak value of electric field is given as

$E_o = 868 N/C$

Now we have relation between electric field and magnetic field as

$B_o = \frac{E_o}{c}$

$B_o = \frac{868}{3\times 10^8}$

$B_o = 2.9 \times 10^{-6} T$