In those situations, that is the best class sizes for electricity tomfoolery, sprinkled heavily with bravely, and a side of youth assumed immortality.
It is also a good class size to swiftly move bodies, of things get too bad.
I had a similar sized class when I apprenticed as an electrical worker via “future farmers if America” funding.
I learned so many good ways to fix things correctly, and three times that number in “bad” ways to fix things.
Guerrilla learning method with pratical daily needed subjects is SORELY missed now-a-days.
The rules for magic and the rules of existence in most fictional universes are significantly more defined (and, arguably, more solid) than the rules for science and existence in this world.
Even the brush off of “Its magic. I don’t have to explain it,” at least indicates that SOMEONE understands the effect and its relative existence.
If you find 5 people who say that they fully understand a single branch of science then I’d bet all of my money in my pocket that you found them in a padded recovery room sans shoe laces.