Question

What is the total intensity of the sun?

Answer 1

`3.95*10^26W`

Explanation:

The Stefan-Boltzmann law is `L=AsigmaT^4`, where:

• `A` = surface area (`m^2`)
• `sigma` = Stefan-Boltzmann (`~5.67*10^-8Wm^-2K^-4`)
• `T` = surface temperature (`K`)

Given the sun is a sphere (though not a perfect one), we can use:
`L=4pir^2sigmaT^4`

`T` is known to be `5800K` and `r` is known to be `7.00*10^8m`

`L=4pi(7.00*10^8)^2(5.67*10^-8)(5800)^4=3.95*10^26W`