That's a pretty specific question! I think you'd probably do better asking Max Planck experts than classical music experts. I didn't even know he was a musician!
Yeah -- even we who actually studied him probably don't know much. All I know is, there's something called Planck's constant, and for some reason it's "h." I don't remember the number, or what it represents, just that it's "h."
And if I were studying it now, I'd demand to know, why is it called a "constant"? Aren't all kinds of other numbers and things constant too? So, why is Planck's thing called a constant, but not those other things?
BTW I appreciate knowing he was a musician. I know that Einstein played violin (sort of).
Besides that, I didn't know that any of those people were particularly into music....
Not to stereotype according to looks, but, does this look like someone who played music?
....oh wait a minute, this is what he looked like when he was younger:
So, Scriabin maybe?
P.S. I looked up a little stuff to see if I could easily find something about the music. I didn't, but....I see that he had more than his share of tragedy. However he might have looked at any time is nothing alongside all that.
P.P.S. I did find this page
, which has this:....a musical evening at the Plancks' house in Berlin, in which Planck, Einstein and a professional cellist played Beethoven's Piano Trio in B-flat major. "Listening to this was marvellously enjoyable, despite a couple of unimportant slips from Einstein... Einstein was visibly filled with the joy of the music and smiled in a light-hearted way that he was ashamed of his dreadful technique. Planck stood quietly by with a blissfully happy face and, hand on heart, said 'That wonderful second movement!'
BTW there are actually at least 2 Beethoven Piano Trios in Bb -- the Archduke and Op. 11. It's a good guess that this was the Archduke.