Question

What is the first law od thermodynamics? How is this law applicable to the Earth's energy balance?

Answer 1

The first law of thermodynamics says that the change in internal energy of a system ΔU equals the net heat transfer into the system Q plus the work done on the system.

`ΔU=Q+W`

Explanation:

A body in space (Earth) is being radiated by a star, the Sun, and then if it remains at a constant temperature, it must radiate out as much energy as it receives.
 #->#the balance of incoming and outgoing radiation on Earth

So, if the temperature `T` of the gas increases`->` the Earths atmosphere, the gas molecules speed up and the internal energy #U# of the gas increases (#ΔU# is positive). If heat exits the gas#->#the Earths atmosphere, `Q` will be a negative number.