d. A carbon resistor is to be used as a thermometer. On a winter day when the temperature is 32°F, its resistance is measured to be 220 2. What is the temperature on a hot summer day when the resistance is 214 Q?

1. Two cylindrical bars, each with diameter of 2.20 cm, are welded together end to end. One of the original bars is copper and is 0.380 m long. The other bar is iron and is 0.190 m long. What is the resistance between the ends of the welded bar at 20°C? (The resistivity of copper and iron can be obtained from the textbook) Ω

Multiple-Concept Example 9 reviews the concepts that are important to this problem. A light bulb is wired in series with a 117-0 resistor, and they are connected across a 120.0-V source. The power delivered to the light bulb is 21.3 W. What is the resistance of the light bulb? There are two possible answers. Give the larger of the two. Light bulb R2 P V

A geological core sample is taken at a coal mine.   The sample is a cylinder 20.7 feet long and 5.25 inches in diameter. The geologists run electric current through the sample to find its resistivity, which can be used to determine the quality of the coal. A voltage of 5030 V (5.03 × 103 V) is found to produce 11.4 mA of current through the sample. a. What is the resistance in the coal sample? b. What is the resistivity of the sample?