What is the difference between the meaning of 'he has worked hard' and 'he worked hard '?
"he has worked hard" it is a present perfect tense.
when somebody says you that "he has worked hard."
it means that he worked hard in near past means his hard work just been completed
it is a complete and perfect action....everybody knows that present perfect tense express near past.
he worked hard indicates simple past tense it means
when somebody says you that "he worked hard" it means that his work completed in the past. presently no need to mention his work....
all in all there is a tense related difference...mainly difference between near past and past..
so, don't be confused...