1. Power Rating of the Electric Heater:
– The power rating of the electric heater is 1500 watts (W).

2. Time Duration:
– The time duration for which we want to calculate the energy used is 10 hours.

3. Formula for Energy Calculation:
– The formula to calculate energy (in joules) is: Energy = Power × Time

4. Conversion of Time:
– Convert the time duration from hours to seconds because the power is given in watts.
– 10 hours = 10 x 60 x 60 seconds = 36,000 seconds

5. Calculation of Energy Used:
– Energy Used = Power × Time
– Energy Used = 1500 W x 36,000 s
– Energy Used = 54,000,000 J

6. Conversion to Kilowatt-Hours (Optional):
– To express energy in kilowatt-hours (kWh), divide the energy in joules by 3.6 x 10⁶ (since 1 kWh = 3.6 x 10⁶ J).
– Energy Used in kWh = (54,000,000 J)/(3.6 x 10⁶ J/kWh)
– Energy Used in kWh = 15 kWh

Therefore, the electric heater rated at 1500 W will consume 54,000,000 joules of energy or 15 kilowatt-hours of energy in 10 hours of operation.