An electric heater is rated 220V, 550W. (i) What does this statement

1.	An electric heater is rated 220V, 550W. (i) What does this statement mean? (ii) Calculate the electrical energy consumed in 3 hours? (iii) Electrical energy is also measured in kWh. What do you understand by a kilo-watt-hour?
Answer» (i) The statement means that the heater should be connected to 220V Supply and that it consumes 550W power. (ii) Energy consumed in 3hrs = (550 x 3)/1000 = 1.65Kwh = 1.65 x 3600 = 5940KJ. (iii) The energy consumed in a resistor when the potential difference is 1V and 1A current flows for 1000 hrs.

An electric heater is rated 220V, 550W. (i) What does this statement mean? (ii) Calculate the electrical energy consumed in 3 hours? (iii) Electrical energy is also measured in kWh. What do you understand by a kilo-watt-hour?

Answer»

(i) The statement means that the heater should be connected to 220V Supply and that it consumes 550W power.

(ii) Energy consumed in 3hrs = (550 x 3)/1000 = 1.65Kwh = 1.65 x 3600 = 5940KJ.

(iii) The energy consumed in a resistor when the potential difference is 1V and 1A current flows for 1000 hrs.