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5. [-/1.42 points] DETAILS MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Residential building codes typically require the use of 12-gauge copper wire (diameter 0.205 cm) for wiring receptacles. Such circuits carry currents as large as 20.0 A. If a wire of smaller diameter (with a higher gauge number) carried that much current, the wire could rise to a high temperature and cause a fire. (Table of resistivities) (a) Calculate the rate at which internal energy is produced in 1.15 m of 12-gauge copper wire carrying a current of 20.0 A. w (b) Repeat the calculation for a 12-gauge aluminum wire. w Explain whether a 12-gauge aluminum wire would be as safe as a copper wire. This answer has not been graded yet. Need Help? Read It Watch It 6. (-/1.42 points) DETAILS MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER One wire in a high-voltage transmission line carries 1 000 A starting at 380 kV for a distance of 170 mi. If the resistance in the wire is 0.500 /mi, what is the power loss due to the resistance of the wire? MW Need Help? Read It Watch It 7. [-/1.48 Points] DETAILS MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A certain toaster has a heating element made of Nichrome wire. When the toaster is first connected to a 120-V source and the wire is at a temperature of 20.0°C), the initial current is 1.73 A. The current decreases as the heating element warms up. When the toaster reaches its final operating temperature, the current is 1.49 A. (a) Find the power delivered to the toaster when it is at its operating temperature. w (b) What is the final temperature of the heating element? ос

Answer 1

Given sia of we wise ld) = 0.205 cm (12 gauge) current flow through Cu wire (1): 200 a) Internal energy pro duced in lol6m length cu wire (8) = 0.017 1.68X108 am Cu wire The resistivity of Resistance (R) SA 8 4 1 Td2 x 1.1584 wire For 12- sm = 1.68x10 a X10.205 x 102) = 5.858103 2 Internal energy of wire = heat produced by = I²R (20)²x x 5.858 10 3 2.34 W ② find internal energy of 12-gauge Al wire Resistivity of Al wire 2.65 x 108 Resistance (R) : sd 481 nd? - 2.65*108 x 4x1.15 = 7.28% Tot X 10.205X103)2 9.230103 R Internal energy of Al wire = Heat produced by 1²R (20) ²x 9. 23x103 = 3.692 W а wire

as = 10DO A n The wire (CU) producing less heat would be safe chances of carching fire will be less 6 Given current carried by wire (I) Length of wire = 170mi Resistance in wire per unit length = 0.5 h Power loss is given as = I² Roh where Lis length of wire. (Press (1000) * 0.54170 2735 75.8 m C - 85 oooooo w S 85 MW