At steady-state, a porch light with a 100 W incandescent bulb produces 97.8 W of heat energy, the rest of its output being visible light. a) What is the efficiency of the light bulb? (use the definition from the class notes)b) How much energy does the bulb consume annually if it is on for an average of 8 hours per day (in kWh)?c) What is the annual cost of the energy at a rate of $0.08/kWh?

a

The efficiency is  =97.8%

b

The Energy consumed is

c

The annual cost is  = $23.36

Explanation:

from the question we are given

        Power supplied = 100 W

        Power Produced  = 97.8 W

  The Efficiency can be  evaluated as

                                                                    =97.8%

To obtain the energy consumed  in a year

     We have to known that

             1 year  = 365 days

           Total hours  = 8 * 365 = 2920 hours [Since 8 hours is used in one day]

           and the 2920 hours obtained = (292× 3600) = 10,512,000 sec

 Energy = Power ×  Time

              =  (100 × 10512000) W.sec

Generally

So ,Energy in (Kwh)  

Given that the rate should be  $0.08/kWh

           The Annual cost would be  

answer:

put more,

answer:

what

explanation: