Question

In a solar system far, far away the sun's intensity is 400 W/m2 for an inner planet located a distance R away. What is the sun's intensity for an outer planet (in W/m2) located at a distance of 4 R from the Sun

Answer 1

I₂ = 25 W / m²

Step-by-step explanation:

Intensity is defined as the relationship between power and area

I = P / A

the power emitted by the sun is constant

P = I A

for the two points of interest

I₁ A₁ = I₂ A₂

energy is distributed on the surface of a sphere

A = 4π R²

I₁ R₁² = I₂ R₂²

I₂ =
`(R_1^2)/(R_2^2) \ I_1`

let's calculate

I₂ =
`(R^2)/((4R)^2) \ 400`

I₂ = 25 W / m²