In a particular area of the country, electrical energy costs $0.12 per kilowatt-hour. (Round your answers, in dollars, to at least two decimal places.) (a) How much does it cost to operate an old-style incandescent 100-W light bulb continuously for 24 hours? $ (b) A modern LED light bulb that emits as much visible light as a 100-W incandescent only draws 16.0 W of power. How much does it cost to operate this bulb for 24 hours? $ (c) A particular electric oven requires a potential difference of 220 V and draws 20.0 A of current when operating. How much does it cost to operate the oven for 5.30 hours? $

a) cost = $ 0.29 , b) cost = $ 0.046 ,  c) cost = $ 2.80

Explanation:

a) Let's find the energy consumed by this bulb, which is the product of the power and time

         energy = P t

         energy = 100 24 = 2400 W h

as the cost of energy is given in kWh we reduce this value

         Energy = 2400 Wh (1 kW / 1000W)

         Energy = 2.40 kWh

Calculate the cost of energy

           cost = 0.12 2.40

           cost = $ 0.288

           cost = $ 0.29

b) energy = 16.0  24 = 384 Wh

we reduce to kWh

      energy = 0.384 kWh

      cost = 0.12 0.384

      cost = $ 0.0461

      cost = $ 0.046

c) let's find the power consumed by the oven

       P = I V

       P = 20.0 220

       P = 4400 W

we look for the energy consumed

       energy = 4400  5.30

       energy = 23320 Wh

we reduce to kWh

       energy = 23.32 kWh

we calculate the cost of this energy

       cost = 0.12 23.32

       cost = $ 2,798

       cost = $ 2.80

force required to detach it is given by

charges are taken to be fundamental charge

now we have

so above is the minimum distance at which it will detach

the answer is the index of refraction of the second medium is higher. i just took the test.