| Chronology | Current Month | Current Thread | Current Date |
| [Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
|
Here's a simple experiment I'm having trouble with. Our
grade 9 science text suggests experimenting with different voltage miniature
screw ligntbulbs operated at the same voltage. The purpose is to find the
relationship between the resistance of the bulb and the illumination produced by
the bulb.
I tried 3 bulbs (1.5 V, 3.8 V, 6V) sequentially wired
to the same 1.5 V drycell.
The least light is obtained with the 6 V bulb and the most
light with the 1.5 V bulb, as I would have anticipated. But here is where
it gets complicated. I would expect that the greatest the voltage rating of
the bulb, the highest would be its resistance and lowest its
current.
The current and resistance values were obtained with a digital
multimeter. Here are the results:
1.5 V bulb 3.8 V
bulb 6 V bulb
1.6 ohms 2.9
ohms 1 ohm
0.22 A
0.18 A
0.28 A
The results were consistant with different bulbs from the same
batch, and were triple verified. Please
enlighten...
|