A coil of 300 turns is wound uniformly on a ring of non-magnetic material. The ring has a mean circumference of 40 cm and a uniform cross-sectional area of 4 cm2. If the current in the coil is 5 A, the magnetic field strength is ______.
1
2250 A/m
2
1500 A/m
3
3750 A/m
4
2400 A/m