Energy billing calculation: If a device uses 600 W of electric power continuously for 60 hours, how much electrical energy is consumed in kilowatt-hours (kWh)?

Introduction / Context:
Utilities bill energy in kilowatt-hours. Converting power usage over time to kWh is an essential practical skill for estimating electricity costs and comparing the efficiency of appliances and power supplies.

Given Data / Assumptions:

• Power P = 600 W.
• Operating time t = 60 h.
• We assume constant power over the interval.

Concept / Approach:
Energy in kWh is computed as (power in kW) * (time in hours). Convert watts to kilowatts by dividing by 1,000, then multiply by hours of operation.

Step-by-Step Solution:

Verification / Alternative check:
Compute in watt-hours: 600 W * 60 h = 36,000 Wh. Convert to kWh by dividing by 1,000 → 36 kWh. Both methods agree.

Why Other Options Are Wrong:

• 3.6 kWh: Off by a factor of 10 (would match 600 W for 6 h).
• 10 kWh and 1 kWh: Result from incorrect time or power conversion assumptions.

Common Pitfalls:

• Forgetting to convert W to kW or misreading hours vs minutes.

Final Answer:
36 kWh