German Lamps in the US

Lösung

According to the Ohm's Law voltage and amperage are proportional to each other if the resistance is the same. If, for example, the voltage drops from 230 V down to 110 V, the amperage also drops! You can see that in these two pictures. The pictures show the German supply voltage (230 V) and the American supply voltage (110 V):

Glühlampe bei einer Spannung von 230 V
light bulb with a voltage of 230 V
Glühlampe bei einer Spannung von 110 V
light bulb with a voltage of 110 V

In the left picture the voltage is 230 V and the amperage about 270 mA (0,27 A). In the right picture the voltage is 110 V, the amperage is about 200 mA (0,2 A). Accordingly, amperage is always lower if there is a lower voltage.
Electric power is voltage multiplied by amperage:

electric power = voltage · amperage

Both voltage and amperage are lower in the right picture. This means that also the electric power in the right picture must be lower. You can see this in the dimmer light of the bulb.

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