Балкански 2004, Теория — Задача 2. Exercice : Measure of the refraction index of a liquid

Concours Général de Physiques “Minko Balkanski” — May 15th 2004 · 15 май 2004 г.

Указания

The two problems are unrelated to each other.

All the answers must be given in English or in French. The clarity and precision will be taken into account for the final note.

The exam is 4 hours long.

Условие

A laser emits a beam at 45° downwards to a mirror at the bottom of a recipient filled with liquid of depth h; the reflected beam rises at 45° to a vertical screen. Horizontal distances L and L are marked between the laser, the mirror's vertical and the screen, and the vertical distance L from the laser level to the liquid surface; labels: Laser, Screen, Mirror, 45°, L, h.

A laser beam is reflected on a mirror placed on the bottom a recipient like on the figure above. When the recipient is empty, the laser beam spot is observed on a screen right in front of the laser. The distance LL is 10cm10cm, and the angle of incidence of the beam is 45∘45^{\circ} according to the mirror.

While the recipient is being filled with a liquid of dept h=1.0cmh = 1.0cm, the laser beam spot undergoes a distance of Δx=0.7cm\Delta x = 0.7cm on the screen.

What is the refraction index nn of the liquid ?

Решение

Внимание: Непълно решение

В архива няма официално решение на тази задача.

Оригинал в Архива: CGP_2004_en.pdf