Mathematical and Physical Journal
for High Schools
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Problem P. 4548. (May 2013)

P. 4548. A metal sphere is initially charged to a potential difference of U0, and is hung by a totally insulating thread. Then it is left in the air of resistivity \varrho=2\cdot 10^{16}\,\Omega\cdot\rm m. How long does it take that the voltage of this condenser decreases to U0/2?

(5 pont)

Deadline expired on June 10, 2013.


Sorry, the solution is available only in Hungarian. Google translation

Megoldásvázlat. \(\displaystyle T=\ln2\cdot \varrho\, \varepsilon_0\approx 34~\)óra.


Statistics:

27 students sent a solution.
5 points:Antalicz Balázs, Asztalos Bogdán, Balogh Menyhért, Blum Balázs, Büki Máté, Csathó Botond, Dinev Georgi, Fehér Zsombor, Forrai Botond, Garai Zoltán, Janzer Barnabás, Jenei Márk, Kollarics Sándor, Kovács 444 Áron, Olosz Balázs, Papp Roland, Rózsa Tibor, Sal Kristóf, Sárvári Péter, Szabó 928 Attila, Trócsányi Péter, Váli Tamás, Varju Ákos.
3 points:1 student.
2 points:1 student.
1 point:1 student.
0 point:1 student.

Problems in Physics of KöMaL, May 2013