What are b,c,and d? Problem 18.88 Part A Battery-powered electricity is very exp
ID: 1533634 • Letter: W
Question
What are b,c,and d?
Problem 18.88 Part A Battery-powered electricity is very expensive compared with that available from a wall receptacle Estimate the cost per kWh of an alkaline D-cell (cost $1.70).This battery can provide a continuous current of 22 mA for 770 h at 1.4V Express your answer using two significant figures. 8/kWh My Answers Cost/kWh = 72 Submit Give Up Correct Part B Estimate the cost per kWh of an alkaline AA-cell (cost $1.25). This battery can provide a continuous current of 22 mA for 100 h at 1.4 V Express your answer using two significant figures. Cost/kWh S/kWh Submit My Answers Give Up Incorrect; Try Again; 13 attempts remaining Part C Compare to normal 120-V ac house current at $0.10/kWh Express your answer using two significant figures. Cost n-cellExplanation / Answer
(b) The power is
P = I * V
= 22*10^-3 * 1.4
= 0.0308 W
The energy is E = 0.0308 * 100
= 3.08 W.h
= 3.08*10^-3 KW.h
The cost is = $ 1.25/3.08*10^-3
= 405.84 $/KW.h
(c) For part a 728 times more expensive than the wall.
For part b 4058 times more expensive than the wall.
(d) The ratio of cost AA cell to cost ac house current is
= $ 405.84/$ 0.10
= 4058