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electrical_engineering_and_electronics_1:block17 [2025/12/02 02:00] – [Materials] mexleadminelectrical_engineering_and_electronics_1:block17 [2025/12/06 13:45] (aktuell) mexleadmin
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 For checking your understanding please do the following exercises: For checking your understanding please do the following exercises:
-  * ...+  * Exercise E2 Toroidal Coil 
 +  * Task 3.2.1 Magnetic Field Strength around a horizontal straight Conductor 
 +  * Task 3.3.2 Electron in Plate Capacitor with magnetic Field
  
 ===== 90-minute plan ===== ===== 90-minute plan =====
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 \\ \\ \\ \\
 <WRAP group> <WRAP group>
-<WRAP column third>+<WRAP>
  
 === Diamagnetic Materials === === Diamagnetic Materials ===
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 </WRAP> </WRAP>
  
-</WRAP><WRAP column third>+</WRAP><WRAP >
  
 === Paramagnetic Materials === === Paramagnetic Materials ===
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 </WRAP> </WRAP>
  
-</WRAP><WRAP column third>+</WRAP><WRAP>
  
 === Ferromagnetic Materials === === Ferromagnetic Materials ===
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 <WRAP> <WRAP>
 <imgcaption BildNr53 | Magnetic field in paramagnetic materials></imgcaption> <imgcaption BildNr53 | Magnetic field in paramagnetic materials></imgcaption>
-{{drawio>Paramagnets.svg}}+{{drawio>Ferromagnets.svg}}
 </WRAP> </WRAP>
  
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 </WRAP></WRAP> </WRAP></WRAP>
  
-==== Applications of the Lorentz Force ==== +==== Applications of the Lorentz ForceTwo parallel Conductors ===
- +
-We want to apply the Lorentz force for two common situations. +
- +
-<WRAP group><WRAP half column> +
- +
-=== Two parallel Conductors ===+
  
 The Lorentz force can be applied to two parallel conductors. \\  The Lorentz force can be applied to two parallel conductors. \\ 
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 \end{align*} \end{align*}
  
-</WRAP><WRAP half column> 
-=== Moving single Charge  === 
- 
-The true Lorentz force is not the force on the whole conductor but the single force onto an (elementary) charge. \\ 
-To find this force the previous force onto a conductor can be used as a start. However, the formula will be investigated infinitesimally for small parts ${\rm d} \vec{l}$ of the conductor: 
- 
-\begin{align*} 
-\vec{{\rm d}F}_{\rm L} = I \cdot {\rm d}\vec{l} \times \vec{B} 
-\end{align*} 
- 
-The current is now substituted by $I = {\rm d}Q/{\rm d}t$, where ${\rm d}Q$ is the small charge packet in the length $\vec{{\rm d}l}$ of the conductor. 
- 
-\begin{align*} 
-\vec{{\rm d}F}_{\rm L} = {{{\rm d}Q}\over{{\rm d}t}} \cdot {\rm d}\vec{l} \times \vec{B} 
-\end{align*} 
- 
-Mathematically not quite correct, but in a physical way true the following rearrangement can be done: 
- 
-\begin{align*} 
-\vec{{\rm d}F}_{\rm L} &= {{{\rm d}Q \cdot   {\rm d}\vec{l}}\over{{\rm d}t}} \times \vec{B} \\ 
-                       &= {\rm d}Q   \cdot {{{\rm d}\vec{l}}\over{{\rm d}t}} \times \vec{B} \\ 
-                       &= {\rm d}Q   \cdot {{{\rm d}\vec{l}}\over{{\rm d}t}} \times \vec{B} \\ 
-\end{align*} 
- 
-Here, the part ${{{\rm d}\vec{l}}\over{{\rm d}t}}$ represents the speed $\vec{v}$ of the small charge packet ${\rm d}Q$. 
- 
-\begin{align*} 
-\vec{{\rm d}F}_{\rm L} &= {\rm d}Q \cdot \vec{v} \times \vec{B}  
-\end{align*} 
- 
-The **Lorenz Force** on a finite charge packet is the integration: 
- 
-\begin{align*} 
-\boxed{\vec{F}_{\rm L} = Q \cdot \vec{v} \times \vec{B}} 
-\end{align*} 
- 
- 
- 
-<callout icon="fa fa-exclamation" color="red" title="Notice:"> 
- 
-  * A charge $Q$ moving with a velocity $\vec{v}$ in a magnetic field $\vec{B}$ experiences a force of $\vec{F_{\rm L}}$. 
-  * The direction of the force is given by the right-hand rule. 
- 
-</callout> 
- 
-</WRAP></WRAP> 
  
  
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 #@HiddenEnd_HTML~202,Result~@# #@HiddenEnd_HTML~202,Result~@#
- 
- 
-</WRAP></WRAP></panel> 
- 
-<panel type="info" title="Task 3.2.2 Superposition"> <WRAP group><WRAP column 2%>{{fa>pencil?32}}</WRAP><WRAP column 92%> 
- 
-<WRAP> 
-<imgcaption BildNr01 | Conductor Arrangement> 
-</imgcaption> 
-{{drawio>Task1LadderArrangement.svg}} \\ 
-</WRAP> 
- 
-Three long straight conductors are arranged in a vacuum to lie at the vertices of an equilateral triangle (see <imgref BildNr01>). The radius of the circumcircle is $r = 2 ~\rm cm$; the current is given by $I = 2 ~\rm A$. 
- 
-1. What is the magnetic field strength $H({\rm P})$ at the center of the equilateral triangle? 
- 
-#@HiddenBegin_HTML~322100,Path~@# 
- 
-  * The formula for a single wire can calculate the field of a single conductor. 
-  * For the resulting field, the single wire fields have to be superimposed. 
-  * Since it is symmetric the resulting field has to be neutral. 
- 
-#@HiddenEnd_HTML~322100,Path~@# 
- 
-#@HiddenBegin_HTML~322101,Solution~@# 
- 
-In general, the $H$-field of the single conductor is given as: 
-\begin{align*} 
-H &= {{I}\over{2\pi \cdot r}} \\ 
-  &= {{2~\rm A}\over{2\pi \cdot 0.02 ~\rm m}} \\ 
-\end{align*} 
- 
-  * However, even without calculation, the constant distance between point $\rm P$ and the three conductors dictates, that the $H$-field has a similar magnitude.  
-  * By the symmetry of the conductor, the angles of the $H$-field vectors are defined and evenly distributed on the revolution:   
-<WRAP> 
-<imgcaption BildNr02 | Conductor Arrangement> 
-</imgcaption> 
-{{drawio>Solution1.svg}} \\ 
-</WRAP> 
-#@HiddenEnd_HTML~322101,Solution ~@# 
- 
-#@HiddenBegin_HTML~322102,Result~@# 
-\begin{align*} 
-            H &= 0 ~\rm{{A}\over{m}}  
-\end{align*} 
- 
-#@HiddenEnd_HTML~322102,Result~@# 
- 
-2. Now, the current in one of the conductors is reversed. To which value does the magnetic field strength $H({\rm P})$ change? 
- 
-#@HiddenBegin_HTML~322200,Path~@# 
- 
-  * Now, the formula for a single wire has to be used to calculate the field of a single conductor. 
-  * For the resulting field, the single wire fields again have to be superimposed. 
-  * The symmetry and the result of question 1 give a strong hint about how much stronger the resulting field has to be compared to the field of the reversed one. 
- 
-#@HiddenEnd_HTML~322200,Path~@# 
- 
-#@HiddenBegin_HTML~322201,Solution~@# 
- 
-The $H$-field of the single reversed conductor $I_3$ is given as: 
-\begin{align*} 
-H(I_3) &= {{I}\over{2\pi \cdot r}} \\ 
-  &= {{2~\rm A}\over{2\pi \cdot 0.02 ~\rm m}} \\ 
-\end{align*} 
- 
-Once again, one can try to sketch the situation of the field vectors: 
-<WRAP> 
-<imgcaption BildNr02 | Conductor Arrangement> 
-</imgcaption> 
-{{drawio>Solution2.svg}} \\ 
-</WRAP> 
- 
-Therefore, it is visible, that the resulting field is twice the value of $H(I_3)$: \\ 
-The vectors of $H(I_1)$ plus $H(I_2)$ had in the task 1 just the length of $H(I_3)$. 
- 
- 
-#@HiddenEnd_HTML~322201,Solution ~@# 
- 
-#@HiddenBegin_HTML~322202,Result~@# 
-\begin{align*} 
-            H &= 31.830... ~\rm{{A}\over{m}} \\ 
-\rightarrow H &= 31.8 ~\rm{{A}\over{m}} \\ 
-\end{align*} 
- 
-#@HiddenEnd_HTML~322202,Result~@# 
- 
- 
-</WRAP></WRAP></panel> 
- 
-<panel type="info" title="Task 3.2.3 Magnetic Potential Difference"> <WRAP group><WRAP column 2%>{{fa>pencil?32}}</WRAP><WRAP column 92%> 
- 
-<WRAP> 
-<imgcaption BildNr05 | different trajectories around current-carrying conductors> 
-</imgcaption> 
-{{drawio>Task3MagneticFieldCurrentFlowingConductor.svg}} \\ 
-</WRAP> 
- 
-Given are the adjacent closed trajectories in the magnetic field of current-carrying conductors (see <imgref BildNr05>). Let $I_1 = 2~\rm A$ and $I_2 = 4.5~\rm A$ be valid. 
- 
-In each case, the magnetic potential difference $V_{\rm m}$ along the drawn path is sought. 
- 
- 
-#@HiddenBegin_HTML~323100,Path~@# 
- 
-  * The magnetic potential difference is given as the **sum of the current through the area within a closed path**. 
-  * The direction of the current and the path have to be considered with the righthand rule. 
- 
-#@HiddenEnd_HTML~323100,Path~@# 
- 
-#@HiddenBegin_HTML~323102,Result a)~@# 
-a) $V_{\rm m,a} = - I_1 = - 2~\rm A$ \\ 
-#@HiddenEnd_HTML~323102,Result~@# 
- 
-#@HiddenBegin_HTML~323103,Result b)~@# 
-b) $V_{\rm m,b} = - I_2 = - 4.5~\rm A$ \\ 
-#@HiddenEnd_HTML~323103,Result~@# 
- 
-#@HiddenBegin_HTML~323104,Result c)~@# 
-c) $V_{\rm m,c} = 0 $ \\ 
-#@HiddenEnd_HTML~323104,Result~@# 
- 
-#@HiddenBegin_HTML~323105,Result d)~@# 
-d) $V_{\rm m,d} = + I_1 - I_2 = 2~\rm A - 4.5~\rm A = - 2.5~\rm A$ \\ 
-#@HiddenEnd_HTML~323105,Result~@# 
- 
-#@HiddenBegin_HTML~323106,Result e)~@# 
-e) $V_{\rm m,e} = + I_1 = + 2~\rm A$ \\ 
-#@HiddenEnd_HTML~323106,Result~@# 
- 
-#@HiddenBegin_HTML~323107,Result f)~@# 
-f) $V_{\rm m,f} = 2 \cdot (- I_1) = - 4~\rm A$ \\ 
-#@HiddenEnd_HTML~323107,Result~@# 
  
 </WRAP></WRAP></panel> </WRAP></WRAP></panel>
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 ===== Embedded resources ===== ===== Embedded resources =====
 Please have a look at the German contents (text, videos, exercises) on the page of the [[https://obkp.mint-kolleg.kit.edu/#OBKP_EDYNAMIK_LADUNGSBEWEGUNG|KIT-Brückenkurs >> Lorentz-Kraft]]. The last part "Magnetic field within matter" can be skipped. Please have a look at the German contents (text, videos, exercises) on the page of the [[https://obkp.mint-kolleg.kit.edu/#OBKP_EDYNAMIK_LADUNGSBEWEGUNG|KIT-Brückenkurs >> Lorentz-Kraft]]. The last part "Magnetic field within matter" can be skipped.
 +\\ \\ \\
 +<WRAP column half>
 +The rotating flux (density) in the stator of a motor, source/CC-BY 3.0 see {{https://commons.wikimedia.org/wiki/File:2HP_1500RPM_induction_motor_no_slip.gif|wikipedia}}
 +{{electrical_engineering_and_electronics_1:2hp_1500rpm_induction_motor_no_slip.gif}}
 +</WRAP>
  
- +<WRAP column half> 
-A living insect ("diamagnet") floats in a very strong magnetic field+A living insect ("diamagnet") floats in a very strong magnetic field \\
 {{youtube>KlJsVqc0ywM?start=45}} {{youtube>KlJsVqc0ywM?start=45}}
 +</WRAP>
  
 \\ \\ \\ \\
-Explanation of diamagnetism and paramagnetism +<WRAP column half> 
-<WRAP> +Explanation of diamagnetism and paramagnetism \\ 
-<WRAP column half>{{ youtube>u36QpPvEh2c }}         </WRAP> +{{ youtube>u36QpPvEh2c }}         
-<WRAP column half>{{ youtube>pniES3kKHvY?300x500 }} </WRAP>+
 </WRAP> </WRAP>
 +<WRAP column half>
 +In Oxygen magnetic? \\
 +{{ youtube>pniES3kKHvY?300x500 }} 
 +</WRAP>
 +
  
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