# Resolving Electric Circuit Questions: C & D

• Miike012
In summary, the individual is using the equation P=IV to solve questions c and d on a paint document. The equation gave a correct answer for question d, but not for question c where the individual got 9/2 instead of the correct answer of 4.3. They are unsure if this answer is close enough or if they are using the wrong equation. They are asked to show more of their work and consider the internal resistance of the battery when finding the voltage at the 9V battery terminals. The individual is then asked to use KVL and Ohm's law to find the potential drop across the internal resistance.
Miike012
Question is in paint doc... question c and d are what I am interested in...

For both questions I used P=IV, this gave me a correct answer for d but not c. For c I got 9/2 the answer is 4.3. Is that close enough? Or am I using the wrong equation?

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Miike012 said:
Question is in paint doc... question c and d are what I am interested in...

For both questions I used P=IV, this gave me a correct answer for d but not c. For c I got 9/2 the answer is 4.3. Is that close enough? Or am I using the wrong equation?

P =iv = 0.5a(9.0v)

Miike012 said:
P =iv = 0.5a(9.0v)

Ah. Well the power supplied by the battery is the power as delivered to external connections at its terminals. The batteries each include an internal resistance, so the voltage at the "9V" battery's terminals is not going to be 9V...

is there an equation to find the voltage at the 9V battery terminals?

Miike012 said:
is there an equation to find the voltage at the 9V battery terminals?

KVL, Ohm's law. What's the potential drop across the internal resistance?

Would it be 3?

Why did you guess 3?

## What is the difference between series and parallel circuits?

Series circuits are circuits where the components are connected in a single path, meaning the current flows through each component in the same direction. Parallel circuits, on the other hand, have multiple paths for the current to flow through, with each component connected to its own branch of the circuit.

## How do I calculate the total resistance in a series or parallel circuit?

In a series circuit, the total resistance is found by simply adding up the individual resistances of each component. In a parallel circuit, the total resistance is calculated using the formula 1/Rtotal = 1/R1 + 1/R2 + ... + 1/Rn, where R1, R2, etc. are the resistances of each component.

## What is Kirchhoff's voltage law and how is it applied?

Kirchhoff's voltage law states that the sum of the voltage drops in a closed loop must be equal to the sum of the voltage sources in the same loop. This law is applied by setting up a loop in the circuit and using the equation ∑V = 0, where ∑V is the sum of all voltage drops and voltage sources in the loop.

## How do I determine the direction of current flow in a circuit?

The direction of current flow in a circuit is determined by the direction of the voltage source. Current always flows from the positive terminal of a voltage source to the negative terminal.

## What is the purpose of using a multimeter in circuit analysis?

A multimeter is a versatile tool used in circuit analysis to measure voltage, current, and resistance. It is essential in identifying faulty components and troubleshooting circuit problems.

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