How many kWh of energy does a 550-W toaster use in the morning if it is in operation for a total of 5.0 min? At a cost of 9.0 cents/k Wh, estimate how much this would add to your monthly electric energy bill if you made toast four mornings per week.

0.0458 kWh

6.5736 cents

Explanation:

The formula for electric energy is given as

E = Pt ... Equation 1

Where E = Electric energy, P = Electric power, t = time.

Given; P = 550 W, t = 5 min = (5/60) h = 0.083 h.

Substituting into equation 1

E = 550 (0.083)

E = 45.83 Wh

E = (45.83/1000) kWh

E = 0.0458 kWh.

Hence the kWh = 0.0458 kWh.

If the makes a toast four morning per week, and the are Four weeks in a month.

Total number days he makes toast in a month = 4*4 = 16 days.

t = 16*0.083 h = 1.328 h.

Total energy used in a month = 550 (1.328)

E = 730.4 Wh

E = 0.7304 kWh.

If the cost of energy is 9.0 cents per kWh,

Then for 0.7304 kWh the cost will be 9.0 (0.7304) = 6.5736 cents.

Hence this would add 6.5736 cents to his monthly electric bill