Question

How much does it cost to operate a 27-W porch light for 24 h if electric energy costs 8¢/kWh?

a) $1.44

b) $2.88

c) $3.84

d) $5.76

Answer 1

The cost to operate a 27-W porch light for 24 hours with an electricity cost of 8 cents per kWh is approximately 5.2 cents.

Step-by-step explanation:

To calculate the cost of operating a 27-W porch light for 24 hours, we use the formula:

Cost = Power (kW) × Time (h) × Electricity rate ($/kWh)

First, convert the power from watts to kilowatts:

27 W = 0.027 kW

Next, multiply the power by the time it is used:

0.027 kW × 24 h = 0.648 kWh

Finally, multiply the energy used by the cost per kWh:

0.648 kWh × $0.08/kWh = $0.05184

Therefore, the total cost to operate the light for one day is approximately $0.05184, which is about 5.2 cents.