(a)[2]
State what the term internal energy of a system means.
(b(i))[3]
Use the first law of thermodynamics to explain how the internal energy of a spring changes when it is stretched at constant temperature and remains within its elastic limit.
(b(ii))[3]
Use the first law of thermodynamics to explain how the internal energy of a sample of water changes when it evaporates from a rain puddle on a hot day.