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4. A resistor is connected across the terminals of a 3.00-V battery, which delivers 1.20 x 105 ) of energy to the resistor in 16 hours. What is the resistance of the resistor? Ω 5. A coil of wire has a resistance of 38.0 1 at 25°C and 43.7 at 55°C. What is the temperature coefficient of resistivity? (Cº) 7. A tungsten wire has a radius of 0.076 mm and is heated from 20.0 to 1450 °C. The temperature coefficient of resistivity is a = 4.5 x 10' (C). When 240 V is applied across the ends of the hot wire, a current of 1.1 A is produced. How long is the wire? Neglect any effects due to thermal expansion of the wire. m 8. A blow-dryer and a vacuum cleaner each operate with a voltage of 120 V. The current rating of the blow-dryer is 12 A, and that of the vacuum cleaner is 3.0 A. (a) Determine the power consumed by the blow-dryer. w (b) Determine the power consumed by the vacuum cleaner. w (c) Determine the ratio of the energy used by the blow-dryer in 13 minutes to the energy used by the vacuum cleaner in one-half hour. Ebd / Ev