Long Metal Tube Figure $24-31$ shows a section of a long, thinwalled metal tube of radius $R$, with a positive charge per unit length $\lambda$ on its surface. Derive expressions for $|\vec{E}|$ in terms of the distance $r$ from the tube axis, considering both (a) $r>R$ and (b) $r<R$. Plot your results for the range $r=0$ to $r=5.0 \mathrm{~cm}$, assuming that $\lambda=2.0 \times$
$10^{-8} \mathrm{C} / \mathrm{m}$ and $R=3.0 \mathrm{~cm}$. (Hint:
Use cylinderical Gaussian surfaces, coaxial with the metal tube.)