兩個 50W 燈泡和一個 100W 燈泡比較，哪種較光？

家用的電器裝置都是並聯.

2009-10-31 22:07:34 補充：
We Can Demostrate By Calculations.

In 100W,220V,
After Calculated,We've Got 0.45A,489 Ohms.

In 50W,220V,
After Calculated,We've Got 0.22A,1000 Ohms.

If One 100W Connected In 220V,
Since The Resistance Is 489 Ohms,So The Current Is 0.45A.

If One 50W Connected In 220V,
Since The Resistance Is 1000Ohms,So The Current Is 0.22A.

If Two 50W Connected In SERIES In 220V,
Since The Resistance Is 1000+1000 Ohms Altogether,So The Current Is 0.11A,

If Two 50W Connected In PARRLLEL In 220V,
Since The Resistance Is 500 Ohms Altogether After Calculation,So The Current Is 0.44A.


By After Calculation,


We've Got

0.45A for one 100W,
0.22A for one 50W,
0.11A for two 50W in series,
0.44A for two 50W in parallel.


In Conclusion,

Two 50W Light Bulb Connect In Series Is Blighter Than 100W.







2009-11-02 00:15:32 補充：
oh...sorry..thx you remind me,

my calculation is correct,but th conclusion is wrong xp"

100W Bulb is the most brighttest,its brighter than 50W parallel 0.01A(10mA),
its almost have identical brightness.

兩個 50W 燈泡一齊開著和只開著一個 100W 燈泡， 哪種比較光？

慢慢來，
如果兩個 50W 燈泡並聯連接同一電路上，會比較光，因爲發光既面積多佐。

如果兩個 50W 燈泡串聯連接同一電路上，會暗好多，因爲電流同電壓都細佐。

Assume the values of power rating given for the three bulbs are under the same voltage, e.g. 220v. Then, which one is brighter depends on how the two 50W bulbs are connected.

If the two 50W bulbs are connected in parallel to the power source, they will give a total brightness the same that given by a single 100W bulb.

However, if the two 50W bulbs are connected in series to the power source, each bulb only give (1/4) of its original brightness. That is, the two bulbs together would only give a total brightness equal to half (1/2) of the brightness of a single 50W bulb, i.e. only (1/4) of the brightness given by a 100W bulb.