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14. Electric power is supplied to a kitchen range from 110- volt mains. 



a) If the range takes a current of 9 amperes, what is the resistance of the 



heating coil ? 



b) If power costs 3 cents per kilowatt-hour, how much does it cost per hour 



to run the range ? 



c) If all the energy supplied were used in heating water, how long would it 



take to heat 4 kilograms of water from 20° C. to 100° C. ? 



15. In a certain experiment the current from two dry cells in series divides and 



one part goes through a wire 100 centimeters long having a resistance of 

 2.5 ohms, while the other part goes through two coils in series with each 

 other, one of 4 ohms resistance and the other of 6 ohms resistance, 

 o) Represent the scheme of connections by a diagram. 

 b) If each of the dry cells has an electromotive force of 1.4 volts and an 

 internal resistance of 0.2 ohm, find the current passing through the 

 100-centimeter wire and the current passing through the 6-ohm coiL 



I4t 



