Mathematical and Physical Journal
for High Schools
Issued by the MATFUND Foundation
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# Problem P. 3828. (October 2005)

P. 3828. A coin is observed from a distance of 22 cm.

a) What is the distance between the observer's eye and the image of the coin if a 5-dioptre lens is placed 10 cm away from the eye of the observer.

b) By what factor is the image of the coin observed through the lens and formed on the retina is greater than the image formed on the retina when the lens is not used.

c) Where should the lens be placed if we want the greatest image on the retina?

(5 pont)

Deadline expired on November 11, 2005.

### Statistics:

 106 students sent a solution. 5 points: Bogár 560 Péter, Csire Gábor, Csirmaz Dávid, Csürös Csaba, Deli Gábor, Dombi András, Dudás János, Engedy Balázs, Kacz Krisztián, Konczer József, Kónya 495 Gábor, Matulik Gábor, Molnár 811 Kristóf, Nagy 317 Péter, Nagy 555 Zoltán, Pásztor Attila, Pósa László, Szabó András László, Szaller Dávid, Széchenyi Gábor, Szirmai Péter, Szűcs Gergely, Takátsy Balázs, Tornyai Árpád, Tűri Balázs, Werner Miklós. 4 points: Csorba Sebestyén, Hotzi Bernadette, Meszéna Balázs, Szolnoki Lénárd. 3 points: 9 students. 2 points: 51 students. 1 point: 10 students. 0 point: 5 students. Unfair, not evaluated: 1 solutions.

Problems in Physics of KöMaL, October 2005