From 92202eac9dd94ad4bb9a3ca07b648cd3eab1d982 Mon Sep 17 00:00:00 2001 From: Erik Strand <erik.strand@cba.mit.edu> Date: Wed, 13 Mar 2019 22:31:03 -0400 Subject: [PATCH] Answer 7.2 --- _psets/5.md | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/_psets/5.md b/_psets/5.md index a5aa5c0..d3a8df0 100644 --- a/_psets/5.md +++ b/_psets/5.md @@ -28,6 +28,14 @@ to go, though not all shields are grounded. Salt water has a conductivity ∼4 S/m. What is the skin depth at $$10^4$$ Hz? +$$ +\begin{align*} +\delta &= \frac{1}{\sqrt{\pi \nu \mu \sigma}} \\ +&= \frac{1}{\sqrt{\pi \cdot 10^4 \si{Hz} \cdot \num{1.3e-6} \si{H/m} \cdot 4 \si{S/m}}} \\ +&= 2.5 \si{m} +\end{align*} +$$ + ## (7.3) Integrate Poynting’s vector $$P = E \times H$$ to find the power flowing across a cross-sectional -- GitLab