Mathematical and Physical Journal
for High Schools
Issued by the MATFUND Foundation
 Already signed up? New to KöMaL?

# Problem P. 4494. (December 2012)

P. 4494. All the resistances of the resistors shown in the figure are R=2 M, the capacitance of the capacitor is C=1 F, the voltage of the battery is U=90 V. The switch K is held at its closed position in order to charge the capacitor, and then it is opened.

a) What is the reading on the ideal voltmeter before opening the switch?

b) What is the reading on the voltmeter a short time after the switch was opened?

(4 pont)

Deadline expired on January 10, 2013.

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

Megoldásvázlat. $\displaystyle a)$ 60 V-ot mutat.

$\displaystyle b)$ 80 V-ot mutat.

### Statistics:

 50 students sent a solution. 4 points: Antalicz Balázs, Balogh Menyhért, Barta Szilveszter Marcell, Beke Gabriella, Csáky Pál, Csathó Botond, Csernák Tamás, Czipó Bence, Dávid Bence, Farkas Tamás, Hajdu 343 Martin, Juhász Péter, Kollarics Sándor, Kovács 444 Áron, Nagy Zsolt, Papp Roland, Sárvári Péter, Seress Dániel, Sisák Mária Anna, Stein Ármin, Szabó Sándor-Zsolt, Szilágyi 585 Dezső, Szilágyi András, Tóth Dávid, Ürge László, Varju Ákos, Wiandt Péter. 3 points: Csóka József, Janzer Barnabás, Jenei Márk, Kacz Dániel, Varga Blanka. 2 points: 15 students. 1 point: 2 students. Unfair, not evaluated: 1 solutions.

Problems in Physics of KöMaL, December 2012