An example of whence is saying you'll send a person back to where they came from; from when they came.
Whence came this traveler?
Whence comes this splendid feast?
The dog was coal black from nose to tail, whence the name Shadow.
Whence does he find his strength?
I know whence he comes.
We went home, whence we departed soon after.
Return whence you came.
There was no reply, whence he inferred that all had gone.
From French, whence we get most of our modern cooking terms.
I scored more than you in the exam, whence we can conclude that I am better at the subject than you are.
An example of whence is asking a person where they are from by saying "From whence do you come?"