Physics Cup – TalTech 2023 – Problem 5

By Jaan Kalda (TalTech).

There are three identical point light sources emitting mutually coherent light homogeneously in all directions. The figure below, also available as a GeoGebra file, shows the positions of the local light intensity maxima in the plane defined by the three light sources. These positions are not perfectly accurate because they are calculated on the assumption that the light intensity from a single source does not depend on the distance from it. Reconstruct the positions of the light sources using GeoGebra classic; you can use all its construction tools except the ones which require inputting numerical values or formulas.

Please submit the solution to this problem via e-mail to The first intermediate results for Problem 4 will be published on 5th March, 13:00 GMT. The first hints will appear here on 12th March 2023, 13:00 GMT. After the publication of the first hint, the base score is reduced to 0.9 pts. For full regulations, see the “Participate” tab.