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--- 184_notes:examples:week6_drift_speed [2018/02/03 22:24] – [Solution] tallpaul
+++ 184_notes:examples:week6_drift_speed [2021/06/08 00:49] (current) – schram45
@@ Line 1: / Line 1: @@
+[[184_notes:current|Return to current in wires]]
 =====Example: Drift Speed in Different Types of Wires=====
 Suppose you have a two wires. Each has a current of  $5 \text{ A}$ . One is made of copper (Cu) and has radius  $0.5 \text{ mm}$ . The other is made of zinc (Zn) and has radius  $0.1 \text{ mm}$ . What are the drift speeds of electrons in each wire? You may want to consult the table below.
-{{ 184_notes:6_n_table.jpg?700 |Properties of Metals}}
+[{{ 184_notes:6_n_table.jpg?700 |Properties of Metals}}]
 ===Facts===
@@ Line 18: / Line 20: @@
 ===Approximations & Assumptions===
-  * The wires have circular cross-sections.
+  * The wires have circular cross-sections. This is typical of real wires and allows us to use the diameter of the wire to calculate the area properly.
   * Using the [[184_notes:current|Drude model]] for electrons in the wire - the electrons are accelerated by the electric field, until they run into a positive nucleus, which reduces the speed back to zero.
 ===Representations===
   * We represent electron current as  $i=nAv_{avg}$ .
   * We represent current as  $I=|q|i$ . Current is charge per second. Electron current is electrons per second. We multiply by  $q$  (the electron charge) to get charge per second.
-  *
 ====Solution====
 We can use the [[184_notes:current|Drude model]] for electrons in the wire - the electrons are accelerated by the electric field, until they run into a positive nucleus, which reduces the speed back to zero. This is where our definition of drift speed comes from, so it is worth including it in our solution for reference.