Same sound - different letters

Yes they all sound exactly the same.

I think I understand your question.

The answer is "No".  There is absolutely no difference, not even the most subtle hint of a shade of a nuance of any difference whatsoever between the pronunciation of  write and right, night and knight, or any other such groups you might care to list.

CJ

the problem with English spelling is that we borrow and have borrowed an infinite amount of words over the years but have never been good about changhing the original orthography when we take these words into our writing system; thus, we have many words that don't seem to conform to any particular systematic way of representing sound in letters.  If you look more closely, you can see patterns for certain sound representations.  For example, 'ck' is only used to represent the sound at the end of a word in spelling.  This can be seen in words like book, stack, flick, pick, etc.  At least some of these spellings of words might be linked to this phenomena.  The difference in spelling can also be seen as an advantage though.  Despite being pronunced the same way, the words that you introduced are definately different words so the different method of spelling eliminates confusion in writing if the context in which the word appears would not provide enough detail to distinguish which word is being used.  You might want to take up some etymological study and look at the root of words, especially those from Latin, Greek, and French that would not only greatly assist you in deducing the semantics behind new words but also to reason out the spelling. 
It's late here, maybe I should have used some simpler sentence structures here, especially if the question was posted by a non-native speaker.

this also reminde me of a joke me and my friends have that we alway's use while driving.

"I wanna turn left, right?"

"Right, left."