Final answer:
The cost to operate a 25-W soldering iron for 8 hours at an energy cost of 8.0 cents per kWh is 1.6 cents.
Step-by-step explanation:
To calculate the cost to operate a 25-W soldering iron for 8.0 hours when energy costs 8.0 cents per kWh, we first need to determine the total energy consumption in kilowatt-hours (kWh). This can be calculated by multiplying the wattage of the device (in kilowatts) by the number of hours it is used. So first, we convert the wattage from watts to kilowatts:
25 watts = 0.025 kW
Next, we calculate the energy consumption:
Energy consumed = Power (in kW) × Time (in hours) = 0.025 kW × 8 hours = 0.2 kWh
Now, we can calculate the cost:
Cost = Energy consumed × Cost per kWh = 0.2 kWh × 8 cents/kWh = 1.6 cents
Therefore, the correct answer is D. 1.6 cents.