Mathematical and Physical Journal
for High Schools
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I want the old design back!!! :-)

Problem P. 4720. (March 2015)

P. 4720. The operation of the demister is the following: a fan blows the air towards a cooled surface, and the condensed water vapour is collected in a container. How much heat is given off to the air in the room by the demister, rated at 180 W, in 15 hours, if it collected 4 litres of water? The temperature of the room is \(\displaystyle 25~{}^\circ\)C.

If the demister is considered to be a heat pump, what is its coefficient of performance (the ratio of the released heat to the electrical energy consumed)?

(4 pont)

Deadline expired on April 10, 2015.


29 students sent a solution.
4 points:Fehér Balázs, Fekete Panna, Fülöp Erik, Németh 017 András, Olosz Balázs, Páhoki Tamás, Szentivánszki Soma , Szépfalvi Bálint.
3 points:Radnai Bálint.
2 points:19 students.
1 point:1 student.

Problems in Physics of KöMaL, March 2015