Power Rating of a Resistor. The power rating of a resistor is the maximum power the resistor can safely dissipate without too great a rise in temperature and hence damage to the resistor. A 100.0 Ω and a 150.0 Ω resistor, both rated at 2.00 W, are connected in series across a variable potential difference. What is the greatest this potential difference can be without overheating either resistor, and what is the rate of heat generated in each resistor under these conditions?
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Combining Resistors in Series & Parallel
Problem 5c
Textbook Question
A triangular array of resistors is shown in Fig. E26.5. What current will this array draw from a 35.0 V battery having negligible internal resistance if we connect it across ac?


1
Identify the resistors in the circuit that are connected between points a and c. In this case, the resistors are 14.0 Ω, 8.0 Ω, and 15.0 Ω.
Determine the configuration of these resistors. The 14.0 Ω and 8.0 Ω resistors are in series, and their combination is in parallel with the 15.0 Ω resistor.
Calculate the equivalent resistance of the 14.0 Ω and 8.0 Ω resistors in series using the formula: R_series = R1 + R2. Substitute R1 = 14.0 Ω and R2 = 8.0 Ω.
Calculate the total equivalent resistance of the circuit by finding the parallel combination of the series resistance (from step 3) and the 15.0 Ω resistor using the formula: 1/R_parallel = 1/R_series + 1/R3. Substitute R3 = 15.0 Ω.
Use Ohm's Law to find the current drawn from the battery. Ohm's Law states that I = V/R_total, where V is the voltage of the battery (35.0 V) and R_total is the total equivalent resistance calculated in step 4.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Ohm's Law
Ohm's Law is a fundamental principle in electronics that states the current through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance. It is expressed as I = V/R, where I is the current, V is the voltage, and R is the resistance. This law is essential for calculating the current in the circuit when the voltage and resistance are known.
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Series and Parallel Circuits
In electrical circuits, resistors can be arranged in series or parallel configurations. In a series circuit, resistors are connected end-to-end, and the total resistance is the sum of individual resistances. In a parallel circuit, resistors are connected across the same two points, and the total resistance is found using the reciprocal formula: 1/R_total = 1/R1 + 1/R2 + ... + 1/Rn. Understanding these configurations is crucial for determining the equivalent resistance in complex circuits.
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Combining Capacitors in Series & Parallel
Kirchhoff's Circuit Laws
Kirchhoff's Circuit Laws consist of two rules: the Junction Rule and the Loop Rule. The Junction Rule states that the total current entering a junction equals the total current leaving it, ensuring charge conservation. The Loop Rule states that the sum of the voltage gains and losses around any closed loop in a circuit must be zero. These laws are vital for analyzing circuits with multiple loops and branches, helping to solve for unknown currents and voltages.
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Kirchhoff's Junction Rule
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