Peak amplitudes of E and H fields (Poynting Vector)

[equation3]

Homework Statement

What are the associated peak amplitudes of the E and H fields if sunlight has a maximum intensity of 1400 W/m² on the earth’s moon?

Homework Equations

I = <s> = 1/2 c ε₀E²

The Attempt at a Solution

I = <s> = 1/2 c ε₀E₀²

1400 = (1/2)(3*10⁸)(8.85*10^-12)(E₀²)

1400 / (1.328*10^-3) = E₀² = 1.05422 * 10⁶

E₀ = √ (1.05422 * 10⁶) = 1026.75 V/m

So the peak amplitude of the E field = E₀ = 1026.75 V/m. I'm not sure how to find the H field though.

B = E₀ / c = 3.42 * 10⁶ T

I'm not really sure how to get from B to H though.

 

[ehild]

I'm not really sure how to get from B to H though.

It is a very basic formula: B=μH

 

[equation3]

Ahhh! Thank you @ehild :)

H = B₀/μ = 3.42 * 10⁶ / 1.26 * 10^-6 = 2.72155 A/m

 

[rude man]

Got the same results. But the problem assumes a monochromatic power emitter so the computation is for that equivalent scenario.