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+### Statement
+
+$8.1.1.$ [Insert the problem statement]
+
+### Solution
+
+The electric current is defined by:
+
+$i = \frac{dq}{dt}$
+
+but $dq = e dn$, where e is the fundamental electrical charge and $dt = ds/c$, where c is the speed of light.
+
+$i = ce \frac{dn}{ds}$
+
+we can approximate $\frac{dn}{ds}$ to $\frac{n}{\ell}$, son
+
+$i \simeq \frac{cen}{\ell} = 0.02\;\rm{A}$
+
+b) Again, electric current can be expressed as
+
+$i = \frac{dq}{dt} \simeq \frac{e}{t}$ (1)
+
+Applying Newton Second Law:
+
+$\frac{e^2}{4\pi\varepsilon r^2} = \frac{m_e v^2}{r}$
+
+where $v = \frac{2\pi r}{t}$,
+
+$t = \sqrt{\frac{16 (\pi r)^3 m_e}{e^2}}$ (2)
+
+Putting (2) into (1),
+
+$i = \sqrt{\frac{e^4}{16m_e(\pi r)^3}} = 0.0012\;\rm{A}$
+
+#### Answer
+
+[Insert a concise answer or boxed result]