Question

What are the (time varying) amplitudes of the E and H fields if summer sunlight has an intensity of 1150 W/m2 in any Town?

Answer 1

Explanation:

Given that,

Intensity = 1150 W/m²

(a). We need to calculate the magnetic field

Using formula of intensity

$I=\dfrac{E^2}{2\mu_{0}c}$

$E=\sqrt{2\times I\mu_{0}c}$

Put the value into the formula

$E=\sqrt{2\times1150\times4\pi\times10^{-7}\times3\times10^{8}}$

$E=931.17\ N/C$

Using formula of magnetic field

$B = \dfrac{E}{c}$

Put the value into the formula

$B=\dfrac{931.17}{3\times10^{8}}$

$B=0.0000031039\ T$

$B=3.10\times10^{-6}\ T$

(b). The relative strength of the gravitational and solar electromagnetic pressure forces of the sun on the earth

We need to calculate the gravitational force

Using gravitational force

$F=\dfrac{Gm_{s}M_{e}}{r^2}$

Put the value into the formula

$F=\dfrac{6.67\times10^{-11}\times1.98\times10^{30}\times5.97\times10^{24}}{(1.496\times10^{11})^2}$

$F=3.522\times10^{22}\ N$

We need to calculate the radiation force

Using formula of force

$F_{R}=\dfrac{I}{c}\pi\timesR_{E}^{2}$

Put the value into the formula

$F_{R}=\dfrac{1150}{3\times10^{8}}\times\pi\times(6.378\times10^{6})^2$

$F_{R}=4.8\times10^{8}\ N$

The gravitational and solar electromagnetic pressure forces of the sun on the earth

$\dfrac{F_{G}}{F_{R}}=\dfrac{3.522\times10^{22}}{4.8\times10^{8}}$

$\dfrac{F_{G}}{F_{R}}=7.3375\times10^{13}$

Hence, This is the required solution.