Question

The sunlight reaching Earth has maximum electric field of 810 Vm⁻¹. What is the maximum magnetic field in this light?

Answer 1

Given :
Electric field amplitude, E₀ = 810 V/m

Maximum value of magnetic field = Magnetic field amplitude = B₀ = ?
We know :

Speed of a wave = `E/B`

For electromagnetic waves, speed = speed of light

`B_0 = u_0  ε_0  cE_0`

Putting the values in the above relation , we get : 

`B_0 = 4pi xx 10^-7 xx 8.85 xx 10^-12 xx 3 xx 10^8 xx 810`

`B_0 = 4 xx 3.14 xx 8.85 xx 3 xx 81 xx 10^-10`

`B_0 = 27010.9 xx 10^-10`

`B_0 = 2.7 xx 10^-6  "T" = 2.7  "uT"`