Mathematical and Physical Journal
for High Schools
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Problem P. 4252. (April 2010)

P. 4252. A strongly short-sighted man wore on both eyes glasses of power -12 dioptres. The lenses were 2 cm from his eyes. In a cataract operation plastic lenses were implanted in his eyes, with which now he can see sharply the book held 25 cm away from his eyes. He is surprised by the fact, that he sees not only better than before, but he sees the book and the letters inside also bigger than before, with the glasses.

a) How much larger does the man see now the objects, which are 25 cm from his eyes, than before the operation he saw the objects, which were 25 cm away from his glasses?

b) Determine the power of the glasses (in dioptres) he needs to see sharply the Moon in the sky.

(5 pont)

Deadline expired on May 10, 2010.

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

Megoldás. \(\displaystyle a)\) \(\displaystyle 1,\!3\)-szor látja nagyobbnak a betűket.

\(\displaystyle b)\) Kb. \(\displaystyle -4\) dioptriás szemüveg kell.


14 students sent a solution.
5 points:Kungl Ákos Ferenc, Laczkó Zoltán Balázs, Lőrincz Dóra, Patartics Bálint, Varju 105 Tamás, Várnai Péter, Zsámboki Richárd.
4 points:Galzó Ákos Ferenc, Jéhn Zoltán, Kaposvári István.
3 points:1 student.
2 points:2 students.
0 point:1 student.

Problems in Physics of KöMaL, April 2010