Question

"Close the door! We aren't heating the outdoors!" is a phrase my father used, especially in the winter. As a matter of fact, all energy consumption eventually turns into heat, which becomes part of Earth's heat. Wikipedia gives the total energy consumption in 2008 to be 15 TW (15 terawatts = 15 x 1012 W). We can spread this power out over the entire surface area of the Earth to calculate the radiative forcing equivalent of the direct use of energy to be _____ W/m2. The radiating area of the Earth is 4Ï R2, where the radius of the Earth is about 6366 km. (watch your unit conversions).

Answer 1

Answer:

I = 2,945 10⁻² W / m²

Explanation:

In this exercise it is requested to calculate the intensity of radiation that is defined by the power per unit of ares

           I = P / A

Approach the Earth as a sphere, with area

         A = 4π R²

Let's replace

           I = P / 4π R²

Let's reduce the magnitudes

      W = 15 10¹² W

       R = 6366 km (10³ m / 1km) = 6.366 10⁶ m

Let's calculate

       I = 15 10¹²/4π (6.366 10⁶)²2

       I = 2,945 10⁻² W / m²

This is a very small amount compared to the intensity coming from the Sun 1353 W / m²