Hi RITESHkakkar,
all your questions are general electronics questions. This is a gold refining forum.
I suggest that you use a computer or electronics forum to ask your questions. Wikipedia is also a good source for general information.
Or just google it...
https://www.google.com/search?q=%22hard+disk%22+%22voice+coil
You already got a good answer above but still continues to ask questions. We do not spoon feed people here, we assume that our members take their time to do a bit of reading and research on their own accord.
I moved this thread into general chat and your other questions have been removed.
Göran