The formula for measuring the actual P=W/t of electrical appliances with watt-hour meter is divided into two steps: the first step is to find out the consumed electric energy W=n turns /n notation according to the turns on the watt-hour meter, where n is the actual turns and the n notation is the rated parameter on the watt-hour meter; the second step is to record the time t for rotating these turns, and p = w/t..

According to the counter of the electric energy meter: W=n revolutions /n minutes; P=W/t

According to the number of turns of aluminum plate W=n turns/(n min t)

Now only one light bulb is connected indoors, and the turntable is measured to rotate for 3 minutes 15. Using these data, it is calculated that the electric energy consumed by the light bulb during this period is _ _ _ _ kWh.

The last vacancy lacks the condition of rated parameters, so it is impossible to find out how much power is consumed, and only an expression W= 15/n can be found.