Draw circles, half plane, angles

Question

How can I draw

A circle with center z and radius R. A circle with center z and radius r, smaller than R. Label above and below the radius R, label just above radius r.

Three consecutive half-planes, one inside another, which are formed by 3 consecutive vertical lines. I want the color of the background of each strip, that the consecutive vertical lines create, to fade from the first to the last, but the vertical lines still be visible. Finally in each strip I need 3 labeled horizontal lines, crossing each strip.

Answer 1

I hope to have interpreted correctly what you want. UPDATE: I hope to addressed your requests. (The first one I did not understand, but you said you can do it yourself. ;-)

\documentclass[border=1mm,tikz]{standalone}
\usetikzlibrary{calc,positioning,shadings}
\begin{document}

\begin{tikzpicture}
\node[circle,draw,minimum width=5mm,fill=black,label=below:$z$]  (z) at (0,0) {};
\node[circle,draw,minimum width=3cm,draw,label=above:$R$,label=below:$R$] at (z){};
\node[circle,draw,minimum width=2cm,draw,label=below:$r$] at (z){};
\end{tikzpicture}

\begin{tikzpicture}
\foreach \Color/\Label [count=\X] in {red/label 1,green/label 2,blue/label 3}
{
\draw[thick](3*\X,-2) -- (3*\X,2);
\draw[left color=\Color] (3*\X,-2) rectangle ($(3*\X,2)+(3,0)$);
\draw[thick](3*\X,0)--++(3,0)node[above,midway]{\Label};
}
\end{tikzpicture}
\end{document}