A frost-free refrigerator uses about 640 kWH of electrical energy per year.

Express this amount of energy in
J:
kJ:
Cal:

http://www.unitconversion.org/power/kilowatts-to-joules-per-hour-conversion.html

To convert the energy from kilowatt-hours (kWh) to joules (J), we need to multiply the energy in kWh by the conversion factor of 3,600,000.

1 kWh = 3,600,000 J

Therefore, to convert 640 kWh to joules:

640 kWh * 3,600,000 J/kWh = 2,304,000,000 J

So, 640 kWh is equal to 2,304,000,000 J.

To convert the energy from kilowatt-hours (kWh) to kilojoules (kJ), we simply multiply the energy in kWh by 1,000.

1 kWh = 1,000 kJ

Therefore, to convert 640 kWh to kilojoules:

640 kWh * 1,000 kJ/kWh = 640,000 kJ

So, 640 kWh is equal to 640,000 kJ.

To convert the energy from kilowatt-hours (kWh) to calories (Cal), we need to multiply the energy in kWh by the conversion factor of 859.8.

1 kWh = 859.8 Cal

Therefore, to convert 640 kWh to calories:

640 kWh * 859.8 Cal/kWh = 550,272 Cal

So, 640 kWh is equal to 550,272 Cal.