Day 11 - Ohm's Law

Practical application of Ohm's law with lightbulb:

We needed to make a complete system where a light bulb would light up, with only one wire and a battery. We were able to accomplish this and in order to make it brighter we simply doubled the power supply.

For this next experiment we chose a resistor and connected it to an ammeter and power supply. We knew the voltage because we were able to control it from the supply. We continually increased the voltage for each test and the actual measured values for the voltage and current for our group and our neighboring group are given below.

The other group appeared to have a smaller resistor, so it would make sense that their current values would be higher than ours for similar voltage. It should be noted to focus on the measured values because their measured values were not the same as ours for each trial.

The graph above shows that there is a linear and directly proportional relationship between the voltage and current. It was also noted that the slope of the lines are actually the values of the resistors, which makes perfect sense. Our group's resistance was 28.3 while the other group's was 17.7. This makes sense now why they would have higher current values compared to us. 

Copper vs. Nickel-Silver

For the next series of tests we were given a series of coils that differed in diameter and length for the wires that were wrapped around them. Only one was copper while the rest were some combination of nickel and silver. We measured the resistance of each coil and the data is shown below. We found that the meter had an error of 1.9 ohm's because we corrected it by finding the actual resistance of the power meter itself.

It is evident that the resistance increases along with the length of the coil.

The graph shows a directly proportional relationship between the length and resistance. The effect that Area has on resistance is actually inverse, since we tested two coils with the same length but different diameters, and the resistance decreased with a larger diameter.