From: Andrew Lorimer <andrew@lorimer.id.au>
Date: Mon, 12 Nov 2018 03:13:22 +0000 (+1100)
Subject: Neap 2018 exam analysis & cheatsheet
X-Git-Tag: yr11~1
X-Git-Url: https://git.lorimer.id.au/notes.git/diff_plain/d4d98e797c0109366eaf5acf69acf806113a3b6e?ds=inline

Neap 2018 exam analysis & cheatsheet
---

diff --git a/physics/exam-analysis.xlsx b/physics/exam-analysis.xlsx
index 233b616..7233296 100644
Binary files a/physics/exam-analysis.xlsx and b/physics/exam-analysis.xlsx differ
diff --git a/physics/final.pdf b/physics/final.pdf
index 8d0ab78..58d19fb 100644
Binary files a/physics/final.pdf and b/physics/final.pdf differ
diff --git a/physics/final.tex b/physics/final.tex
index 1db6640..9a64a9d 100644
--- a/physics/final.tex
+++ b/physics/final.tex
@@ -190,9 +190,11 @@
 % -----------------------
   \subsection*{Energy and work}
 
+  Total energy = mass energy
+
     $E_{\text{rest}} = mc^2, \quad E_K = (\gamma-1)mc^2$
 
-    $E_{\text{total}} = E_K + E_{\text{rest}} = \gamma mc^2$
+    $E_{\text{total}} = \gamma E_{\text{rest}} = E_K + E_{\text{rest}} = \gamma mc^2$
 
     $W = \Delta E = \Delta mc^2=(\gamma-1)m_{\text{rest}} c^2$
 
@@ -249,18 +251,18 @@
 
     \[v=\sqrt{GM \over r} = \sqrt{gr} = {{2 \pi r} \over T}\]
 
-    \[T={\sqrt{4 \pi^2 r^3 \over {GM}}}\tag{period}\]
+    \[T={\sqrt{4 \pi^2 r^3 \over {GM}}}=2 \pi \sqrt{r_{\text{alt}} \over g_{\text{alt}}}\tag{period}\]
 
     \[r = \sqrt[3]{{GMT^2}\over{4\pi^2}}\tag{radius}\]
 
 % -----------------------
   \subsection*{Magnetic fields}
-    \begin{itemize}
-      \item field strength $B$ measured in tesla
-      \item magnetic flux $\Phi$ measured in weber
-      \item charge $q$ measured in coulombs
-      \item emf $\mathcal{E}$ measured in volts
-    \end{itemize}
+    % \begin{itemize}
+    %   \item field strength $B$ measured in tesla
+    %   \item magnetic flux $\Phi$ measured in weber
+    %   \item charge $q$ measured in coulombs
+    %   \item emf $\mathcal{E}$ measured in volts
+    % \end{itemize}
 
     % \[{E_1 \over E_2}={r_1 \over r_2}^2\]
 
@@ -290,6 +292,8 @@
 
     \textbf{Right hand grip:} thumb points to $I$ (single wire) or N (solenoid / coil)
 
+    \textbf{Magnet through ring:} consider $g$
+
     \includegraphics[height=2cm]{graphics/slap-2.jpeg}
     \includegraphics[height=3cm]{graphics/grip.png}
 
@@ -303,6 +307,8 @@
 
     \textbf{Xfmr} core strengthens \& focuses $\Phi$
 
+    \columnbreak
+
 % -----------------------
   \subsection*{Particle acceleration}
 
@@ -311,6 +317,7 @@
     e- accelerated with $x$ V is given $x$ eV
 
     \[W={1\over2}mv^2=qV \tag{field or points}\]
+    \[V_{\text{point}} = (V_1 - V_2) \div 2 \tag{if midpoint} \]
     \[v=\sqrt{{2qV} \over {m}}\tag{velocity of particle}\]
 
     Circular path: $F\perp B \perp v$
@@ -331,14 +338,13 @@
       {\item Series $V$ shared within branch}
     \end{itemize}
 
-    \includegraphics[height=4cm]{graphics/ac-generator.png}
-
 % -----------------------
   \subsection*{Motors}
 % \begin{wrapfigure}{r}{-0.1\textwidth}
 
     \includegraphics[height=4cm]{graphics/dc-motor-2.png}
-    \includegraphics[height=3cm]{graphics/ac-motor.png} \\
+    % \includegraphics[height=3cm]{graphics/ac-motor.png} \\
+    \includegraphics[height=4cm]{graphics/ac-generator.png} \\
 
     Force on I-carying wire, not Cu \\
     $F=0$ for front & back of coil (parallel) \\
@@ -439,7 +445,7 @@
   \subsection*{Refraction}
   \includegraphics[height=3.5cm]{graphics/refraction.png}
 
-  When a medium changes character, light is \emph{reflected}, \emph{absorbed}, and \emph{transmitted}. $\lambda$ changes, not $f$.
+  When a medium changes character, light is \emph{reflected}, \emph{absorbed}, and \emph{transmitted}. $\lambda$ changes, not $f$. $n$ changes slightly with $f$ (dispersion)
 
   angle of incidence $\theta_i =$ angle of reflection $\theta_r$
 
@@ -549,7 +555,7 @@ $f \cdot V$ & ${h \over q}$ & $f_0$ & $-\phi \over q$ &
     \item $E$ and $f$ of photon: $E_2 - E_1 = hf = {hc \over \lambda}$
     \item Ionisation energy - min $E$ required to remove e-
     \item EMR is absorbed/emitted when $E_{\operatorname{K-in}}=\Delta E_{\operatorname{shells}}$ (i.e. $\lambda = {hc \over \Delta E_{\operatorname{shells}}}$)
-    \item No. of lines - include all possible states
+    \item No. of lines - include all possible states. \Delta E \ne |\Delta E|
   \end{itemize}
 
   \subsection*{Uncertainty principle}
@@ -562,8 +568,8 @@ $f \cdot V$ & ${h \over q}$ & $f_0$ & $-\phi \over q$ &
 
   \subsubsection*{wave model}
   \begin{itemize}
-    \item cannot explain photoelectric effect
-    \item $f$ is irrelevant to photocurrent
+    % \item cannot explain photoelectric effect
+    \item any $f$ works, given $t$
     \item predicts delay between incidence and ejection
     \item speed depends on medium
     \item supported by bright spot in centre
@@ -573,9 +579,10 @@ $f \cdot V$ & ${h \over q}$ & $f_0$ & $-\phi \over q$ &
   \subsubsection*{particle model}
 
   \begin{itemize}
-    \item explains photoelectric effect
+    % \item explains photoelectric effect
     \item rate of photoelectron release $\propto$ intensity
     \item no time delay - one photon releases one electron
+    \item threshold frequency
     \item double slit: photons interact. interference pattern still appears when a dim light source is used so that only one photon can pass at a time
     \item light exerts force
     \item light bent by gravity