Hello Aspirant,

Hope you are doing best.

yes. there are some free online physics certificate courses available...

some of them are... Georgetown Quantum mechanics for every one, understanding Einstein: the special theory of relativity in which they will seek to understand Einstein especially focusing on the special theory of relativity that Albert Einstein, as a twenty six year old patent clerk, introducing in his miracle year of 1905.

so choose field of your interest and then join...

Hope this information helps you...

All the Best.