Day14

Calculate the work done when the charged is particle on the electric field of the rod:

Calculation of the potential energy :

The surface of tow opposite charged particle:

Electric Potential Lab/Activity:

Experiment set up:

Part 1:

 Question 1: 15 voltage means that the power supply gives 15J/C potential energy to the system.

Part 2:Data; Excel table and graph:
The data of the voltage and calculation of change in V/change in x is collected below. Also, the calculation of work done from x=0 to x=3. x=4 to x=6, and x=5 to x=2 also calculated in the spreadsheet.

Graph: Potential vs Position 

Day13

1.Dim/Bright Circuits:

1. Set up a circuit that have the dimmest possible brightness of the light bulb, and another circuit with the brightest possible of the light bulb.

In a series circuit, the light bulb should be  dimmest because in a series circuit, the light bulb's net voltage equals total voltage that the battery has. It means each light bulb has lower voltage. But in the parallel, each light bulb has the voltage is equal to the battery, so it means in the parallel, the voltage is higher than the voltage in the series. Since, the light bulb in the parallel is brightest.

 Ohm's Law:
Experiment set up:
 Set up a power supply (able to change current and voltage) to inside a cup of water. To raise up the voltage and current to heat up the water in the cup. And record the changing.

Then, we calculated the theoretical value of final temperature of water can be raised by putting recorded voltage(hot, energy) into the water.

We calculated the theoretical value of final temperature of water is 53.2, but in the fact, the temperature is 43.1. This error is caused by changing in voltage and current. And during the heating, the some of energy and hot has already lose. Since, the true temperature is lower than the theoretical temperature.

Day12

1. Light a Bulb

 To make a bulb light using a battery, a wire, and a bulb.

We can set up with two different ways to make bulb lights.

1. Put bulb on positive side

2. Put bulb on negative side

To make a bulb light using two batteries, a wire, and a bulb.

2. Charge Detector

Professor Mason uses the charge detector to demonstrates how the charge detector works. 

1.  Rubs a balloon with a head and brings it near the charge detector and the light goes to yellow(The charge detector flicks couples times and stays on the red light. The red light means that the object near the charge detector has negative charge. )

2.  A positive object goes near the charge detector, the light turns from red to yellow.

3. A battery put near the charge detector, the light remain unchanged. (net charge is zero)

2.Ammeter: a device that measure the current in a circuit.It only can be used as wire because it's resistance is very small. In the experiment blew, the ammeter is a wire. It is connected with a voltage, light, and switch. We close the switch, then we look at the light. It is lighting.

The graph voltage vs times and current vs times: The shape of the graph is almost the same between voltage and current is direct proportional.

Uses the same set up to connect with three different resistors:  it shows three different slop lines, and its their slop is 16.69, 5.045, and 1.969, and it means that the resistors values are 16.69,5.045, and 1.969. The resistor equals to V/I

Day11

1. Gauss’s Law in Flatland

2. Gauss’s Law in Three Dimensions

3. Microwave Demos
1  Put Metal fork into microwave---nothing visible happens
2  Put CD into microwave.--- CD is burned
3  Put fire into microwave.---fire gets larger.
4  Put light into microwave.---to be lighter but the light is broken soon.
5  Put a soap into a microwave.--- Nothing happen
6  Put a purple metal ball into the microwave.---got burn and the fire changes color.

Summary:

In today’s class, we learn what is flux and Gauss’s Law. We know that flux is calculated by the number of electric field lines, and its go through the surface area. And we know how microwave works and how it can heat things up. We also learn what kind of material is able to absorb microwave and what  kind of material is not able to absorb microwave. 

5% Extra Credit on Celebration One

Day 10

ActivPhysics

Questions 1-9 were answered with the simulation below.

3+ Charge

Denser lines=Higher Force

1+ Charge

1- Charge

In this lab we first charge put a cylinder cage with aluminum foil inside. predicting which direction the aluminum foil will go. 

But it only outside foil move up because the flux of inside is zero, the number of electric field coming in  and electric out is the same.