A small bulb is rated at 5.9 W when operated at 125 V. The tungsten filament has a temperature coefficient of resistivity a = 4.5 x 10-3/ °C. When the filament is hot and glowing, its temperature is 122 °C. Calculate the following (In canvas enter only the answer to part b) a) The resistance of the filament when it is at the operating temperature. b) The resistance when the temperature of the filament drops to 20°C (i.e. when the lamp is off). c) At 10 cents per kWh, what will be the cost of operating the light-bulb for 100 hours.

A small bulb is rated at 5.9 W when operated at 125 V. The tungsten filament has a temperature coefficient of resistivity a = 4.5 x 10-3/ °C. When the filament is hot and glowing, its temperature is 122 °C. Calculate the following (In canvas enter only the answer to part b) a) The resistance of the filament when it is at the operating temperature. b) The resistance when the temperature of the filament drops to 20°C (i.e. when the lamp is off). c) At 10 cents per kWh, what will be the cost of operating the light-bulb for 100 hours.

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter21: Current And Direct Current Circuits

Section: Chapter Questions

Problem 21P

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