Question

On a cloudless day, the sunlight that reaches the surface of the earth has an intensity of about 1.40 × 10 3 1.40×103 W/m². What is the electromagnetic energy contained in 6.00 m³ of space just above the earth's surface?

Answer 1

Answer;

2.8 × 10^-5 Joules

Explanation;

Considering the base area of the 'space' to be 1m²

Therefore; it's 'height' h = 6.0 m  

Time taken (t) for all the light in this space to travel down 6.0 m ..  

t = h/c

  = 6.0 m / 3.0^8m/s

   t = 2 × 10^-8 s  

Energy reaching this 1 m² base = 1.40 × 10^3 J/s .. (1400W)  

Net energy (E) travelling through this space = 1400J/s x 2 × 10^-8 s  

E = 2.8 × 10^-5 J