A 60 W light bulb at 120 V is left on in your house to prevent burglary, and the power charges 10 cents per kilowatt-hour, how much will it cost to leave the bulb on for 30 days?

(60 W•24hours •30 days)/1000=43.2 kW•h

43.2•0.1$=4.32$

To calculate the cost of leaving the light bulb on for 30 days, we need to determine the amount of energy consumed by the bulb and then calculate the total cost based on the energy consumption rate.

First, let's calculate the energy consumed by the 60 W light bulb in kilowatt-hours (kWh):

Energy (kWh) = (Power (W) × Time (h)) / 1000

Given:
Power (W) = 60 W
Time (h) = 30 days = 30 × 24 hours = 720 hours

Energy (kWh) = (60 W × 720 hours) / 1000 = 43.2 kWh

Next, we need to calculate the cost of the energy consumed by the bulb. The cost is given as 10 cents per kilowatt-hour (kWh).

Cost = Energy (kWh) × Cost per kWh

Given:
Energy (kWh) = 43.2 kWh
Cost per kWh = $0.10

Cost = 43.2 kWh × $0.10/kWh = $4.32

Therefore, it will cost $4.32 to leave the 60 W light bulb on for 30 days.