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You have discovered Ohm's Law! That is wonderful. Scientists love to discover patterns like this. The next question for you, as a scientist, is: "are there more questions and discoveries hidden in the discovery I just made?" Your law shows how to equate resistance, voltage and current if you have one battery and one resistor. What happens if the circuit has 2 resistors in the loop?
ASL
Can you find a way to make Ohm's Law work for this circuit? The current and voltage are easy. You can just try putting them into the equation. What do you do with the 2 resistances? Do you add, subtract, multiply or divide them?
ASL
Build several circuits with 2 resistors and one battery in series. Put the values into the worksheet "Ohm's Law with 2 resistors in series". Replace the ? between voltage and current with the operation you discovered in the first worksheet. Replace the ? between the resistors with + - / or X to make the statement true.
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In a series circuit with 2 resistors, do you add, subtract, multiply or divide the resistors?
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Does the same operation work if you have 3, 4 or more resistors connected in series?
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What happens if you have 2 batteries in the loop? Can you find a way to make Ohm's Law work for this circuit?
ASL
Build several circuits with 2 batteries and one resistor in series. Put the values into the worksheet "Ohm's Law with 2 batteries in series". Replace the ? between resistance and current with the operation you discovered in the first worksheet. Replace the ? between the voltages with + - / or X to make the statement true.
ASL
In a series circuit with 2 batteries, do you add, subtract, multiply or divide the voltages?
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Does the same operation work if you have 3, 4 or more batteries connected in series?
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Does the same operation work if you have 3, 4 or more batteries connected in series with resistors between them?
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Is the current the same or different at different places in a circuit with several resistors and batteries?
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From Ohm's law we can calculate that .3 amperes of current is following through the following circuit. Check the results to verify the value.
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This current is flowing through all 3 resistors. Use the equation, voltage = resistance ? current with the ? replaced, to calculate the voltage across each of the resistors. Replace .3 amperes for the current and 10 ohms for the resistor. Repeat this using 20 ohms for the other resistor.
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Check your calculations by inserting a voltmeter in the circuit. Check the voltage for each of the 3 resistors.
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By using Ohm's Law you can calculate the current and voltage anywhere in a series circuit.
ASL
What happens if the circuit isn't a series circuit? What if there is more than one path that the electricity can flow through? The next page will help you explore this situation.
