Physics · Current Electricity
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A 40 watt lamp turns half the electrical energy it uses into light energy. How much light energy does it give out is 10 seconds.
- A
400J
- B
200J
- C
800J
- D
20J
The light energy given out in 10 sec is 200J.
Total Power= 40 W
Well 40 W= 40 joules a second = 40 J/s
Efficiency= 50%
Power x efficiency= Actual Power output
40x0.5=20 W
Time x Power = Energy
10 s x 20 W = 200 J
Light Energy = 200 J
The light energy given out in 10 sec is 200J.
The light energy given out in 10 sec is 200J.
The light energy given out in 10 sec is 200J.
Total Power= 40 W
Well 40 W= 40 joules a second = 40 J/s
Efficiency= 50%
Power x efficiency= Actual Power output
40x0.5=20 W
Time x Power = Energy
10 s x 20 W = 200 J
Light Energy = 200 J
The light energy given out in 10 sec is 200J.
The light energy given out in 10 sec is 200J.
Tagged under Physics · Current Electricity · 2001