O A ring made up of equal semicircular section of cast inn and castutool with
two air gaps of olmm and 0.25mm respectively has across sectional area
of 400 cm? and
a mean diameter of sm. The ring is uniforanly wound with a coil
41200tums II the relative permeability of cast iron and cost osteel aro 280061d
400 respectively, determine the corrent required to produce a Flor of lomub in
ring.
the​