1 = 5.0 A coil = 200 turns Radius= 10.0 cm HR = 5500 Diameter = 1.5 cm Ho=47(10-7)H/m gap 0.25 cm

An iron rod with diameter of 1.5-centimeter was formed into an almost perfect circular ring (including the air gap at the joint) having an average centerline radius of 10.0-centimeter. The air gap is 0.25 centimeter in length. A coil of 200 turns was wounded on the ring and a current of 5.0-amperes DC was made to flow using external DC source. Considering magnetic flux fringes on the air gap ,  the effective cross sectional area of the air gap increased by 5% compared to that of the rod. 

Relative Magnetic Permeability of Iron = 5500. 

Consider the average or centerline circumference of the ring as the total magnetic path (rod+airgap).

1. What is the total Reluctance of the ring ( rod + air gap ) (A-turns/Wb) ?

2.What is the magnetic flux generated in the ring?

3. What is the magnetic flux density in the air gap