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P. 4042. A filament lamp rated at 40 W transforms 2% of the total energy to visible light. Suppose that the time of the emission of one photon is 10-14 second. Find the average number of visible photons emitted by the filament at the same time.

(4 points)

Deadline expired on 11 February 2008.

Statistics on problem P. 4042.
 85 students sent a solution. 4 points: 56 students. 3 points: 12 students. 2 points: 5 students. 1 point: 9 students. Unfair, not evaluated: 3 solutions.

• Problems in Physics of KöMaL, January 2008

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