Question

An 11.0-W energy-efficient fluorescent lightbulb is designed to produce the same illumination as a conventional 40.0-W incandescent lightbulb. Assuming a cost of $0.111/kWh for energy from the electric company, how much money does the user of the energy-efficient bulb save during 220 h of use?

Answer 1

Answer:

$Savings = 0.709$

Explanation:

Energy consumed by 11 W energy efficient fluorescent bulb is given as

$E = Power \times time$

now we can say

$E = 11 \times 220h$

$E = 2.42 kWh$

now total cost of the energy used is given as

$Amount = 2.42 \times 0.111$

$Amount = 0.268$

Now for conventional 40 W bulb  we can say

$E = Power \times time$

now we can say

$E = 40.0 \times 220h$

$E = 8.8 kWh$

now total cost of the energy used is given as

$Amount = 8.8 \times 0.111$

$Amount = 0.977$

So total money saving is given as

$Savings = 0.977 - 0.268$

$Savings = 0.709$