Answer:
Explanation:
The magnetic field due to a current carrying coil is given by
[tex]B = \mu _{0}ni[/tex]
Where, μ0 is the permeability of free space, n be the number of turns per unit length and i be the current.
When an iron rod is placed inside, the magnetic field incraeses, because the magnetic field is given by
[tex]B' = \mu _{0}\mu _{r}ni[/tex]
Where, μr is the relative permeability of iron, which is more than 1. So, the magnetic field increases.
