Electric power in Physics: I want to ask, is a bulb marked with 220 V 800 w working for 800 W per hour or not

Electric power in Physics: I want to ask, is a bulb marked with 220 V 800 w working for 800 W per hour or not

220V 800W means that the bulb consumes 800W of rated power per hour under the rated voltage of 220V, that is to say, it consumes 0.8 kwh of electricity per hour, and the municipal power is 1000W = 1 kwh of electricity per hour. If it is not ignited under the rated voltage of 220V, the power will be different

How much energy does an 800W electric furnace consume when it works normally for 15 minutes

1kwh = 1 degree 800W = 0.8kw 15min = 0.25h
So 0.8 * 0.25 = 0.2kwh = 0.2 degree

How many kilowatts of electricity does a 1500W electric power use in 15 minutes
If you can, please list the formula. Thank you!

1 degree = 1 kWh
1500W = 1.5kw
15 minutes = 1 / 4 hours = 0.25 hours
Power consumption 1.5 * 0.25 = 0.375 degree