Is you true the magnetic field around an electromagnet can be made stronger by increasing current or decreasing the number of coils around the iron core?

No, you is false. Increasing current does it, but the number of turns in the coil
also must increase if you want to increase the magnetic field that way.
No, you is false. Increasing current does it, but the number of turns in the coil
also must increase if you want to increase the magnetic field that way.