According to the US Census, there are about 117,000,000 households in the US. If every household replaced 1 60W incandescent bulb that is used for 35 hours per week with a 10W LED bulb, how many kWh of electricity would this save the country per year?

The country is saved 1.0647×10^10 kWh of electricity per year.

Step-by-step explanation:

Power saved per household = 60 W - 10 W = 50 W = 50/1000 = 0.05 kW

Power saved in 117,000,000 households = 117,000,000 × 0.05 kW = 5,850,000 kW

Number of hours the bulb is used per week = 35 hours

Number of hours the bulb is used per year (52 weeks) = 52 × 35 = 1,820 hours

Quantity of electricity saved per year = 5,850,000 kW × 1,820 hours = 1.0647×10^10 kWh

10,647,000,000 kWh per year of electricity is saved.

Step-by-step explanation:

Given:

Time, t = 35 hours/week

In 1 year, assume 52 weeks in 1 year:

35 hours/week * 52 weeks/1year

= 1820 hours/year

Bulb used by households = 60 W

Power of replaced bulbs = 10 W

Power saved per household = 60 - 10

= 50 W

Power saved in 117,000,000 = 117,000,000 × 50

= 5,850,000,000 W

= 5,850,000 kW

Energy saved = power x time

= 5,850,000 × 1820

= 10,647,000,000 kWh per year.