IOM 2017, Блиц — Задача 72

OLYMPIAD OF METROPOLISES. Moscow, September 4 · 4 септември 2017 г.

Условие

A thin converging lens refracts the ray of light symmetrically as shown in the figure. Calculate the focal length of the lens (in cm).

A thin converging lens (blue) on a horizontal axis; a red ray crosses the axis 10 cm to the left of the lens, is refracted at the lens and crosses the axis 10 cm to the right; the distances are labelled a = 10 cm and a = 10 cm, and the question f = ? is written in red.

The answer should be given in the SI units unless otherwise stated. If the numerical result turns out to be an integer, it should be given as the answer. Otherwise round the result to the first decimal.
g=10 m/s2g = 10\ \mathrm{m/s^2}.

Отговори

Решение

Оригинал в Архива: blitz.pdf · официални решения: answers-blitz.pdf