EuPhO 2026, experiment — Задача 7. Task E7: Mysterious line (2.5 pts)

Автор: Olympiads XYZ · транскрипция на официалните материали

Проверена срещу оригинала на 13.9.2026 от същия модел, който я е транскрибирал (без независима проверка)

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Съдържание

УсловиеРешение

Experimental task Language: English · 2,5 т.

Внимание: Бележка към темата

Solutions document exists in the archive but was not included in this window; official answers for all tasks are missing.

Условие

When the levitating droplet becomes rather flat, a levitator voltage can be found for which the light from the red LED passing through the droplet forms a sharp horizontal line on the screen behind.

Consider only liquid III for this task.

Hint: For the line to be visible, the LED must be well aligned with the droplet, see Fig. 2.

Photo of all the exam equipment laid out on a table, each item labelled with a white letter A through X: power supply, electrical box, levitator module, stopwatch, screen, syringes, liquids, tweezers, ruler, cables.
Figure 1: Overview of the equipment.
Photo of the levitator mounted on a rail with an LED module attached; white arrows labelled 1 point at two screws for horizontal movement and tilting, and arrows labelled 2 point at two screws for vertical movement and tilting of the LED module.
Figure 2: Alignment of LED module. You can align the setup by using the screws shown in the figure. Arrows labelled 1 are for horizontal movement and tilting of the LED module, and arrows labelled 2 are for vertical movement and tilting of the LED module.

a) Draw a sketch of the ray propagation inside the droplet when the line appears. Use the line phenomenon described above to estimate the refractive index nn of liquid III. (2.5 pts) [2,5 т.]

Решение

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Оригинал в Архива: eupho2026_experiment_problems.pdf · официални решения: eupho2026_experiment_solutions.pdf