Question

The heater element of a toaster is a 5.4 m length of nichrome wire, whose diameter is 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 Ω·m. Assume the toaster is operated at a constant voltage of 120 V. (a) What is the power drawn by the toaster? (b) If the cost of electricity is 12 ¢ per kilowatt-hour, and it takes 2 minutes to toast bread, how much does it cost for toasted bread? (c) Use order of magnitude sense-making to check the reasonableness of your answer to part (b). (d) When the heater element is at room temperature, is the resistivity in the nichrome wire greater than, less than, or equal to its resistivity when at operating temperature? Explain.

Answer 1

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