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Step 5

1. If the torch uses 0.5A, the calculator 0.05A, the cassette player
2A, calculate the resistances.
2. On the back of most electrical devices there is the power rating
SONNY JAPAN
MODEL 36 К
SERIAL #0169423/005
6W 6V
Use this formula for calculating the power of an electrical device
R=I·V
Power, P, is measured in watts (W). The power rating of the device
is 6W.
Calculate the current that is used
P=I·V 6=1·6 6/6=1 I=1A

Look at this table. Fill in the gaps:

electrical device:
power (W)
voltage (V)
current (A)
electric fire light bulb electric drill
2400 W 55 W 990W
240 V 110 V 110 V
------ ----- -----
electric kettle car headlight television
----- 48W 220W
240V 12V 110V
10A ----- -----

Now make statements like this example:
The electric drill has a power rating of 990W. When it is
connected to a main supply of 110 volts it uses a current of 9A.

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