8.03 Resistance and Ohm's Law

Resistance in a Wire Simulation

Open the Resistance in a Wire simulation from PhET.

Follow the directions below and write down answers to the questions in your notebook.

Once you've completed the activity, progress to the next tab to check your answers.

1. What happens to the resistance when the resistivity is increased or decreased?


2. What happens to the resistance when the length of the wire is changed?


3. MWhat happens to the resistance when the area of the wire gets larger?


4. What happens to the resistance when the area of the wire gets smaller?

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Answers: Resistance in a Wire

Below are the answers to the questions from the Resistance in a Wire activity.

1. Answer: The resistance is also increased when resistivity is increased or decreased when resistivity is decreased.


2. Answer: The resistance the resistance decreases when the length of the wire decreases and increases when the length of the wire increases.


3. Answer: The resistance decreases.


4. Answer: The resistance increases.

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Ohm's Law Simulation

Open the Ohm's Law simulation from PhET.

Follow the directions below and write down answers to the questions in your notebook.

Once you've completed the activity, progress to the next tab to check your answers.

1. What happens to the current when the voltage is increased?


2. What happens to the current when the voltage is decreased?


3. What happens to the current when the resistance is increased?


4. What happens to the current when the resistance is decreased?


5. What happens to the voltage when the resistance is increased or decreased?

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Answers: Ohm's Law

Below are the answers to the questions from the Ohm's Law activity.

1. Answer: The current also increases.


2. Answer: The current also decreases.


3. Answer: The current decreases.


4. Answer: The current increases.


5. Answer: It remains the same.

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Ohm's Law Calculation

Solve the following problem using the formula for Ohm's Law. Work through the problem in your notebook and be sure to show your work. Progress to the next tab to check your answer.

Problem: The voltage across a nightlight bulb is 3 V and the bulb's resistance is 6 Ω, what is the current through the bulb?

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Answer: Ohm's Law Calculation

Problem: The voltage across a nightlight bulb is 3 V and the bulb's resistance is 6 Ω. What is the current running through the bulb?

Answer:

1. Identify known and unknown values.

   R = 6 Ω

   V = 3 V

   I = ?



2. Since we are solving for I and it is already isolated on one side of the equation as is, we do not need to rearrange the equation.

   I = V / R

3. Input the values into the rearranged equation and solve.

   I = V / R

   I = (3 V) / (6 Ω)

   I = 0.5 A

4. Answer: The current running through the light bulb is 0.5 A.

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