IYPT 1992, Задачи на турнира — Задача 14. Laser

Problems for the 5th International Young Physicists’ Tournament

Critical edition

Protvino, Russia, June 24‒July 1, 1992 [1]

Critical edition: corrected and commented official translation [2]

FINAL DRAFT. — Please do not re-publish. Suggestions and criticism welcome

Edited and commented by Ilya Martchenko. The original edition’s historical notes, sources and acknowledgments are retained with problem 1.

Условие

A laser beam is directed [27] perpendicularly to the wall of a transparent glass tank [28] filled with water. If the beam passes through the tank above or below the level of the water in the tank, we can observe a spot on the screen behind the tank. If the beam passes along the level of the water we observe a vertical line. Explain the origin of the line and calculate its parameters.

Note [27]

“Directed horizontally”, in the Russian text

Note [28]

“Flat transparent cuvette with water”, not mentioning the material of the walls, in the Russian text. “Glass tank (aquarium)” in the 1992 English text.

Решение

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Оригинал в Архива: 1992.pdf