The heating element of a room heater is rated at 750W when itis operated from a
ID: 1665112 • Letter: T
Question
The heating element of a room heater is rated at 750W when itis operated from a 120V power supply? a)What is the resistance of the heating element? b) If the heating element is made of nichrome wire that is1.0mm in diamenter, how long is the wire? The resistivity ofnichrome is 1x10-6 ohm-m. c) If electricity costs ten cents per KW-hr, how much does itcosts to operate this heater for 2 hours and 45 minutes? Thanks for helping me with this problem.Please remember there are 3 PARTS to this problem and all 3 partsneed to be included in your answer. The heating element of a room heater is rated at 750W when itis operated from a 120V power supply? a)What is the resistance of the heating element? b) If the heating element is made of nichrome wire that is1.0mm in diamenter, how long is the wire? The resistivity ofnichrome is 1x10-6 ohm-m. c) If electricity costs ten cents per KW-hr, how much does itcosts to operate this heater for 2 hours and 45 minutes? Thanks for helping me with this problem.Please remember there are 3 PARTS to this problem and all 3 partsneed to be included in your answer.Explanation / Answer
Power P = 750 W Voltage V = 120 V (a). resistance R = V^ 2/ P = 19.2 ohm (b). Diameter d = 1 mm = 1* 10 ^ -3 m Area of cross section A = d ^ 2/ 4 = 0.785 * 10 ^-6 m^ 2 The resistivity of nichrome = 1x10-6 ohm-m. we know R = L / A from this length of the wire L = RA / = 15.07 m c) electricity cost per KW-hr is N = 10cents time t = 2 hours and 45 minutes = 2hours + 0.75 hours = 2.75 hours energy utilised E = P t = 2062.5 W h = 2.0625 kW -h So, required cost = E N = 20.625 cents c) electricity cost per KW-hr is N = 10cents time t = 2 hours and 45 minutes = 2hours + 0.75 hours = 2.75 hours energy utilised E = P t = 2062.5 W h = 2.0625 kW -h So, required cost = E N = 20.625 centsRelated Questions
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