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Light Intensity question

  • #1
[SOLVED] Light Intensity question

The light (electromagnetic) output of a bulb is 40 W. How much energy passes through a 40 cm^2 area element aligned perp. to the light rays?

I know that I = Power/Area, but I thought that Power = W(aka. energy) /t , and the problem has no reference to time.

What am I missing?
 

Answers and Replies

  • #2
140
0
Without time this question is meaningless.
 
  • #3
Yea we told our teacher, so now the t= 4 seconds, and obviously now the problem is super easy. W=Pt

W= 40 W (4 s)

W=160 J
 

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