I want to know the answer to the following question:
How was the Planck constant calculated in the early 20th century?
All the background I'm provided with is that "In principle, the Planck constant could be determined by examining the spectrum of a black-body radiator or the kinetic energy of photoelectrons, and this is how its value was first calculated in the early twentieth century.". Is that enough to answer the question?
Answer: yes