Voltage, temperature, potential energy, and work in electricity

Understanding battery system:

We started the day doing an experiment on lightbulb and battery again. First, we connect 1 battery to two bulbs and see how the bulbs light. Then, we connect two battery side by side to 1 lightbulb and see how the bulb lights.

The brightness of both trials are equal.

The bulb thats connected to batteries that are side by side is dimmer than when the batteries are stacked up because when the batteries are stacked up, the voltage of both batteries are added, whereas when the batteries are side by side, is the same as using 1 battery voltage. Because of this, using 2 batteries or 1 battery earlier give the same brightness result.

When drawn in a circuit form, there are parts on the circuit that can be drawn to indicate each, which are battery, resistor, bulb, and switch as shown below. 

Understanding relationship between voltage and temperature:

The next experiment is water heater. The Water heater is powered by battery.

The graph below shows the 2 minutes that it is heated.

Then, the voltage is doubled and graphed for the next 2 minutes as shown below. When the voltage is doubled, the scalar factor is multiplied by 4, theoretically because the current is squared in temperature. Thus, the slope is steeper.

Understanding work in electricity:

There are 3 paths that can be taken to move on a slope. Going parallel to the charge then perpendicular, going perpendicular to the charge then parallel, or just going parallel to the slope. We wanted to see the difference in work on each path. Work on a path that's perpendicular to the current is 0. Thus, we only count the work thats parallel to the current. After doing the calculation, the total work for all path turn out to be equal.

When given a current and 3 different ... On it, we want to rank them from the least work to the biggest work. The work perpendicular to the current is zero as we learned because the angle between the current and the .. Is cos 90*, which is zero. This makes the work also becomes zero. The next one would be the .. Slanted to the current, then the ... Parallel to the current as calculated below.

Recall from past lecture, that Electric force is equal to charge multiplied by electric field; then, we can substitute force with them as well.

Understanding potential energy and work:

We now learn that potential energy in electric is equal opposite to work. But we know that work is force times distance, which force is also charge times electric field; therefore, work is integration of charge multiplied by electric field and change in distance. We also know that voltage is work per charge. By equating these equations, we can find the voltage to be integration of electric field multiplied by distance.

Vpython:

Given program as below, we have to predict how it would look in the whiteboard.

We predicted the 2 charges to be on the x-axis, one one (-2,0,0), and the other on (2,0,0). We also predicted the observation point on (-1,0,0).

After making the prediction, we calculate the V total using the given charges in the program, which are (-1 x 10(-9)) and (1 x 10(-9)). We also use the distance from each charges to the observation point. Using this known, we plug it in to the formula of voltage that we have known from earlier, which is kq/r, and add the voltage from both charges. We found the total voltage to be -6V. When the observation point is moved to (1,0,0), we can use the same method and found the voltage to be 6V.

When we run the program in vpython, the screen shows as below, which followed what we predicted.

The next blog will show vpython that we are assigned to do and we are allowed to work together, but we have to remember, "collaborating, not plagiarizing"! :)

~THE END~