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.
Deadline expired on 10 May 2010.