if a current of 4900A is applied to a copper wire what might happen to it? does it burn or what?

Answer 1

It depends on the length and area of the copper wire

Answer 2

Overheating depends upon the diameter, but not the length. It is the resistance per unit length that determines the temperature rise. The length will affect the voltage drop, which must also be considered.

I have not gone through the numbers, but the wire would probably have to be at least 1 inch in diameter to avoid overheating the insulation.