Confirming Ohms Law
CONFIRMING OHM’S LAW BY ALEX KUCHMENKO 9.1
Aim – To Confirm Ohm’s Law through experimentation. Hypothesis – The More Ohms the resistor has, the weaker the current will become. Materials – Power pack, ammeter, voltmeter, resistors, connecting wires. METHOD – 1. POWER PACK
POWER PACK
RESISTOR
RESISTOR
VOLTMETER
VOLTMETER
AMMETER
AMMETER
A
A
V
V
Set up a known resistor in a simple circuit. 2. Vary the voltage and record the potential drop (V) and the current (I) through the resistor. Do this for a number of settings on the power pack, for example do two, four and six volt settings. (Remember the power pack should only be turned on while doing readings.)
2. Vary the voltage and record the potential drop (V) and the current (I) through the resistor. Do this for a number of settings on the power pack, for example do two, four and six volt settings. (Remember the power pack should only be turned on while doing readings.)
Another experiment to perform is to attach several resistors to the circuit, for example a 2.2Ω and a 10Ω would make a 12.2Ω resistor.
4. Construct a line graph of the data in the previous table. Put all three sets of data on the same table.
DISCUSSION – The calculated unknown resistances and line graph confirmed Ohm’s Law because the resistance equals potential over current, or R = V/I. each time, the unknown resistance was approximately equal to the Ohm’s of the resistor, therefore confirming Ohm’s Law. An ammeter is connected in series because its purpose is to measure the current in the circuit, and since it is a low impedance device, connecting it in series would cause a short circuit, damaging the ammeter. Whereas the voltmeters purpose is to measure the electrical potential difference between two points in the circuit. The potential difference
Aim – To Confirm Ohm’s Law through experimentation. Hypothesis – The More Ohms the resistor has, the weaker the current will become. Materials – Power pack, ammeter, voltmeter, resistors, connecting wires. METHOD – 1. POWER PACK
POWER PACK
RESISTOR
RESISTOR
VOLTMETER
VOLTMETER
AMMETER
AMMETER
A
A
V
V
Set up a known resistor in a simple circuit. 2. Vary the voltage and record the potential drop (V) and the current (I) through the resistor. Do this for a number of settings on the power pack, for example do two, four and six volt settings. (Remember the power pack should only be turned on while doing readings.)
2. Vary the voltage and record the potential drop (V) and the current (I) through the resistor. Do this for a number of settings on the power pack, for example do two, four and six volt settings. (Remember the power pack should only be turned on while doing readings.)
Another experiment to perform is to attach several resistors to the circuit, for example a 2.2Ω and a 10Ω would make a 12.2Ω resistor.
4. Construct a line graph of the data in the previous table. Put all three sets of data on the same table.
DISCUSSION – The calculated unknown resistances and line graph confirmed Ohm’s Law because the resistance equals potential over current, or R = V/I. each time, the unknown resistance was approximately equal to the Ohm’s of the resistor, therefore confirming Ohm’s Law. An ammeter is connected in series because its purpose is to measure the current in the circuit, and since it is a low impedance device, connecting it in series would cause a short circuit, damaging the ammeter. Whereas the voltmeters purpose is to measure the electrical potential difference between two points in the circuit. The potential difference