Mathematical and Physical Journal
for High Schools
Issued by the MATFUND Foundation
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Problem P. 4432. (March 2012)

P. 4432. Two lenses are placed such that their principle axes are common, and they are at a distance of 5 cm. One of them is a converging lens of optical power of 10 dioptres and the other is a diverging lens of optical power of -5 dioptres. A small filament lamp is placed 20 cm from the converging lense, not on the side at which there is the diverging lens. Where should the screen be placed in order to gain the sharp image of the filament on it? Where will the image be if the filament lamp is placed closer to the converging lens by one-sixth of the initial 20 cm distance?

(4 pont)

Deadline expired on April 10, 2012.

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

Megoldás. A szórólencsétől 60 cm-re tegyük az ernyőt. A másik esetben sehol nem alakul ki kép, az izzószálról kiinduló fénysugarak párhuzamosan fognak haladni.

Statistics:

 36 students sent a solution. 4 points: Bolgár Dániel, Czipó Bence, Demeter Dániel, Fehér Zsombor, Fonyó Viktória, Forrai Botond, Fülep Andrea , Győrfi 946 Mónika, Horicsányi Attila, Janzer Barnabás, Janzer Olivér, Kacz Dániel, Kulcsár Ildikó, Nagy Zsolt, Pázmán Zalán, Pölöskei Péter Zsolt, Sisák Mária Anna, Szabó 928 Attila, Szász Norbert Csaba, Szigeti Bertalan György, Tatár Dániel, Trócsányi Péter, Varju Ákos, Wiandt Péter. 2 points: 2 students. 1 point: 10 students.

Problems in Physics of KöMaL, March 2012