Mathematical and Physical Journal
for High Schools
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Problem P. 4093. (September 2008)

P. 4093. The light mill (Crookes radiometer) consists of an airtight glass bulb, in which the air pressure is very low, and in which there are four vanes mounted on a vertical spindle, about which they can rotate. The vanes are polished on one side and black on the other. Why and into which direction do the vanes rotate when they are exposed to light?

(4 pont)

Deadline expired on October 13, 2008.


212 students sent a solution.
4 points:143 students.
3 points:17 students.
2 points:5 students.
1 point:27 students.
0 point:20 students.

Problems in Physics of KöMaL, September 2008