The net charge in a current carrying wire is zero. Them, why does a magnetic field exert a force on it?

Explanation

The net charge is zero, which indicates no electric field will be developed by the wire in the surrounding and hence no external electric field can apply force on it. But in the case of a current carrying wire, free electrons are moving which generate magnetic field in their surrounding, so external magnetic field can apply force on them. It is basically an interaction of fields. Two systems having magnetic fields of their own can apply magnetic force on each other, and similarly two systems having electric fields of their own will apply electrie force on each other.