phys: clarify emf

2021-02-09 19:03:10 -05:00 · 2021-02-09 19:03:10 -05:00 · 9a09082835
commit 9a09082835
parent cae592d66e
1 changed files with 4 additions and 1 deletions
--- a/docs/sph3u7.md
+++ b/docs/sph3u7.md
@ -987,7 +987,10 @@ All cells have **internal resistance**, which is the resistance of th cell itsel
 $$P=I^2r$$

 The voltage across the terminals of a battery is equal to, where $I_r$ is the current across the internal resistance:
-$$V_AB=\epsilon-I_r$$
+$$V_{AB}=\epsilon-I_r$$
+
+The total voltage (emf) of a circuit can be found with Ohm's law:
+$$\epsilon=I(R+r)$$

 An **ammeter** measures the current of a load and must be in series with the load. Ideally it should have the lowest resistance possible.