From 49dc3d1fb7bf53df1424ea8a31fd8b17af1bbb31 Mon Sep 17 00:00:00 2001
From: eggy <eggyrules@gmail.com>
Date: Mon, 11 Jan 2021 16:08:55 -0500
Subject: [PATCH] phys: fix intensity formula

---
 docs/sph3u7.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/sph3u7.md b/docs/sph3u7.md
index ba03282..ec91551 100644
--- a/docs/sph3u7.md
+++ b/docs/sph3u7.md
@@ -699,7 +699,7 @@ $$E\propto I\propto A^2$$
 $$E=E_0\cos\theta$$
 
 And so:
-$$I=I_0\cos\theta$$
+$$I=I_0\cos^2\theta$$
 
 When **unpolarised light** passes through a polariser, the average result of $I\cos\theta$ is $\frac{1}{2}$, so the intensity of polarised light is **half** of the intensity of unpolarised light.