Serbian scientist fully prepared to ditch a student on returning (5)
I believe the answer is:
tesla
'serbian scientist' is the definition.
(I've seen this in another clue)
'fully prepared to ditch a student on returning' is the wordplay.
'fully prepared' becomes 'all set' (I've seen this in another clue).
'to ditch' indicates named letters should be taken away.
'a student' becomes 'L' (as in L-plates for learner drivers).
'on returning' says the letters should be written in reverse.
'allset' with 'l' taken away is 'alset'.
'alset' written backwards gives 'TESLA'.
(Other definitions for tesla that I've seen before include "Physics unit" , "Physicist" , "Nikola ---, electricity pioneer" , "Unit of magnetic flux density" , "American scientist" .)