a$.$ Given a material that is having, $lo{n}_r=4\mathrm{.}3$ and $=1\mathrm{.}2{10}^{-6}{}_m.$ Find the nature of this material, numerical values of loss tangent, phase shift constant and attenuation factor at $12$ MHz $.$

$(10$ Marks$)$

b$.$ Brief your understanding of Skin depth for uniform plane waves in various mediums.

$(5$ Marks$)$