If the number of turns of a circular current carrying coil is doubled, then how will the magnetic field produced by it changes?
Doubled
The magnetic field produced by a current-carrying wire at a given point depends directly on the current passing through it. If the number of turns in the circular coil is doubled, the field produced will also get doubled as that produced by a single turn. This is because the current in each circular turn has the same direction and the field due to each turn then just adds up.