What does the zeroth law of thermodynamics allow us to define?

How much heat is required to convert 0.3 kg of ice at 0°c to water at the same temperature

Hydrogen atoms are excited by a laser to the =4n=4 state and then allowed to emit. what is the maximum number of distinct emission spectral lines (lines of different wavelengths) that can be observed from this system? 8 6 2 7 4 5 1 3 calculate the wavelength of the 4⟶14⟶1 transition. =λ=

What is an aquifer for science class