# What is the relation between surface area and radiation, if any?

Basically I wonder what happens to emitted radiation by douubling a light e.g. twice the surface area of the sun will emit how much more radiation? 4 times more? Is there a formula?

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At fixed temperature - and/or fixed chemical composition, even when the radiation is not exactly thermal - the total power radiated is clearly proportional to the area A. –  Luboš Motl Dec 30 '12 at 9:42
... so double the area just means double the radiation. See for example en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law. However note that a star of double the surface area of the Sun will not emit twice the energy since it will be at a different temperature. –  John Rennie Dec 30 '12 at 10:31