Multiple-Concept Example 9 reviews the concepts that are important to this problem. A light bulb is wired in series with a 134-0resistor, and they are connected across a 120.0-V source. The power delivered to the light bulb is 21.1 W. What is the resistance of thelight bulb? There are two possible answers. Give the larger of the two.Number iUnitsLight bulbMP₁VR₂ Modeling the ProblemSTEP 1 Power The power P₁ delivered to the 6.00- resistor is given by P₁ = 1²R₁ (Equation 20.6b), where I is the current through the resistor and R₁ is the resistance.In this expression R₁ is a known quantity, and the current I will be determined in Step 2.STEP 2 Ohm's Law The current I in the circuit depends on the voltage V of the battery and the equivalent resistance Rs of the two resistors in series (see Figure20.15). This dependence is given by Ohm's law (Equation 20.2) asV1 =RsThis result for the current can be substituted into Equation 20.6b, as indicated at the right. Note from the data table that the voltage is given. In Step 3 we will evaluatethe equivalent resistance from the individual resistances R₁ and R₂.STEP 3 Equivalent Resistance Since the two resistors are wired in series, the equivalent resistance Rs is the sum of the two resistances (Equation 20.16):Rs = R₁ + R₂The resistances R₁ and R₂ are known. We substitute this expression for Rs into Equation 1, as shown in the right column.SolutionP₁ = P²R₁?P₁ = P²R₁I=R$I =?P₁ = I²R₁VRsRs = R₁ + R₂(20.6b)(20.6b)(1)(20.6b)(1)(20.16)

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Multiple-Concept Example 9 reviews the concepts that are important to this problem. A light bulb is wired in series with a 134-0 resistor, and they are connected across a 120.0-V source. The power delivered to the light bulb is 21.1 W. What is the resistance of the light bulb? There are two possible answers. Give the larger of the two. Number i Units Light bulb M P₁ V R₂

Multiple-Concept Example 9 reviews the concepts that are important to this problem. A light bulb is wired in series with a 134-0 resistor, and they are connected across a 120.0-V source. The power delivered to the light bulb is 21.1 W. What is the resistance of the light bulb? There are two possible answers. Give the larger of the two. Number i Units Light bulb M P₁ V R₂

Physics for Scientists and Engineers: Foundations and Connections

1st Edition

ISBN:9781133939146

Author:Katz, Debora M.

Publisher:Katz, Debora M.

Chapter29: Direct Current (dc) Circuits

Section: Chapter Questions

Problem 19PQ

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