In a certain city, electricity costs $ 0.18 per kW ⋅ h . What is the annual cost for electricity to power a lamppost for 5.00 h per day with a 100. W incandescent light bulb versus an energy efficient 25 W fluorescent bulb that produces the same amount of light? Assume 1 year = 365 days .

The cost of electricity  for 100 W power bulb = $ 32.85

Cost of electricity for 0.025 W  fluorescent  bulb =  $ 8.2125

Explanation:

Cost of electricity = $ 0.18 per KW-H

Time = 5 hour per day

Bulb power = 100 W = 0.1 KW

Fluorescent bulb power = 25 W = 0.025 KW

(a) Cost of electricity for 100 W power bulb

0.1 × 5 × 365 × 0.18 =  $ 32.85

(b) Cost of electricity for 0.025 W  fluorescent  bulb

0.025 × 5 × 365 × 0.18 = $ 8.2125

Therefore the cost of electricity  for 100 W power bulb = $ 32.85

Cost of electricity for 0.025 W  fluorescent  bulb =  $ 8.2125