Consider a material for which $$r $=1,$ r $=2\mathrm{.}5,$ and the loss tangent is $0\mathrm{.}12.$ If these three values are constant with frequency in the range $0\mathrm{.}5$ MHz$$ f $100$MHz$,$calculate: $($a$)$ at $1$ and $75$ MHz; $($b$)$ at $1$ and $75$ MHz; $($c$)$ p at $1$ and $75$ MHz$.$