last day, june 3rd

Again, it is a lab day. We still work with solving for Vrms and Irms. We draw a diagram to record what we have and what we solve. We used the inductor board and function generator to build our circuit. Based on the formula, we solve for Vrms and Irms.

Later we solve for the power and Vrms and Irms for another inductor, and we draw a graph of the frequency.

This is the diagram that shows our set up, and it also obtains the data for other components we used for this experiment.

May 29

This is the graph we measured in an AC circuit that invloves resistor, capacitor and inductor. This graph is we measured with resistor in an AC circuit.

This is the set up for our circuit.

We write every experimental value and calculated value on it, including Irms and Vrms. Also, we calculated the percent difference between real value and our calculated value.

we use calculus to derive the expression for Vmax, Vrms, Imax and Irms.

This time we measured with capacitor in our AC circuit. This time, we calculated some value we need for this experiment on the white board.

This is the graph we have for our second experiment that involves capacitor. Based on this graph, we find Vmax and Imax, and we show the relationship between V and I.

Same as before, we write our all values and board, and calculate Vrms and Irms, and calculated the percent difference.

This time we involves inductor, based on formula we derived before, we solve for the Irms for the AC circuit.

summary:

It is all experiment, and each experiment takes time to perform. By setting AC circuit with capacitor, inductor and regular resistor, we can easily the difference between those 3 different component in an AC circuit.

Error:

Before today's lab, on May 27, we did a lab that performs same thing, however, we connect with inductor.

Before the experiment, we calculated Vrms and Irms.

This is the graph we got from the AC circuit that connected with inductor.

may 27

We are given an inductor, and we picked a normal resistor. Together with a function generator, we make an AC circuit. This is the inductance and resistance we calculated for the AC circuit.

This is the frequency we calculated for the circuit.

setting the frequency as we calculated, we got this graph.

By changing frequency and function settings, we got this graph.

We continue activities from our lab maual to calculate and observe inductors in an AC circuit.

This is the activity we performed on the internet to help us getting familiar with inductor. Since it is similiar with capacitor, we derive some of those answers based on concept we learn before.

This is answers we had for the activity above.

We also perform a exercise that related to time constant. Within this circuit, we calculated time constant for each loop, and voltage and current change that has inductor and without inductor.

summary:

Inductor is similar to capacitor, and the relationship of voltage and current to time is almost same to those relatioship we learned in capacitor chapter. It has time constant, and the relationship of inductor and magnet is that a changing current in a coil also induces an emf in that same coil. Such a coil is called an inductor, and the relationship of current to emf is described by the inductance

 

Before the exam

We perform an activity that related to change of magnetic flux and the emf.

Within those activity, we observe the relationship of the rate of the change of magnetic flux and the emf produced by the magnetic field.

This is those quedtion we answered for the activity we did above.

We also performed an experiment. This time, we use a bar and let it move in the magnetic field to let the magnetic flux change.

Perform like the experiment, we practice an activity on the computer, and answer some questions like we did at the begining of the class. However, this time, we obtain the velocity of the bar.

We answer the questions from the activity. We observe that the emf if related the velocity of the bar, cause the motion of the bar change the magnetic flux, which produce emf together witht the magnetic field.

We are introduced a new concept, induction. It is similiar to capacitor we talked about before. A changing current in a coil also induces an emf in that same coil. Such a coil is called an inductor, and the relationship of current to emf is described by the inductance

we draw the graph to show the relationship between current and time, and the difference of this relationship between normal resistor and inductors.

This is the third activity we did, and this one practice to observe inductor. We answer some question to observe the relationship and components of an AC circuit that has inductor.

This is answers for question we did for the activity above

Same as capacitor, we have time constant for inductor. however, for capacitor, time constant is RC while for inductor, it is L/R, and the graph is still a function of e to some power that contains time and time constant.

Summary:

change of magnetic in magnetic field produce emf, so there will be many method to produce emf.

Inductor is different from regular resistor, but performs similar like a capacitor, and there is also a time constant for it.

March Guass law

By drawing electric field line, we observe the relationship between electric flux and the enclosed surface.

We draw some electric field line, and we count how many electric line pass through the surface as our electric flux. Based on this, we will observe electric flux deeper.

The top of the equipment is given charge. 2 paper are lifted in side and outside the can. After we start the equipment, the 2 paper reject each other cause there is same type charge on them.

We write the formula to show the relationship between charge, flux.

This is our prediction about the experiment. After watch the experiment, we write our explanation for why it works like this.

We perform a question to use calculus to solve for electric flux.

We put a CD in the microwave, and it begins to burn strongly. Since microwave gives radix to the CD, so that there is current that cause CD burning.

We can see the broken line on the CD, that is where the current flows when it is in the microwave burning.

We perform calculation to determine the electric flux inside a cylinder. Together with find flux outside this cylinder at a certain position, we will find how useful guass law is.

Summarize: eventhough guass law is just a simple formula: Flux = Q/e0, however, it is the most useful formula when we solve for electric flux. 

May 15 1015

In left and right side of a wire that has current pass through, the direction of magnetic field is opposite. We can find the direction by righ hand rule. At this point, we draw the magnetic force applied on the wire to determine their motion.

We perform the experiment to prove our prediction is correct. They attract each other, which matches our prediction.

Later, we write the expression of magnetic on each wire due to the magnetic field cause by the other wire.

We discussed about magnetic field produced by an AC current. Since the direction is changing all the time, so the magnetic field is reversing all the time. As a result, there is no magnetic field in an AC current.

An experiment to record magnetic produced by the current. There is a new equipment that is applied here to detect the magnetic field. We graph he magnetic field respect to time axis, and we got a trig function graph.

In our group we perform same experiment to observe the relationship between number of loops and magnetic field. We predict that the more loops we have, the larger magnetic field at that poiont.

When we record data by logo pro and graph it, the graph generally matches our prediction. after 3 loops, the graph is more linear. We believe that for loop 1 and loop 2 the graph is less linear because we didn't wait for the magnetic go to completely stable to record it.

We draw the magnetic flux through the closed surface. This practice tells us that when we do the cross product, the area vector is vector normal to the surface, not the surface itself.

Not only electric can produce magnet, magnet can also produce electric. This experiment shows that a closed loop moving in a magnetic field causing its flux will produce electric.

Since both magnetic and electric can produce each other. When we put steal ring in it, the motion of the steal in the magnetic whhich produced by the current cause current in the steal ring, and it also produce magnetic field, which cause the motion of the steal ring. If we put some other ring that is non conductive or it is not complete that can't form a closed surface, nothing will happen.

One is Al and the other is glass. if we drop a nonconductive cylinder in the al and magnet cylinder in the glass, they will fall at the same time due to free fall. What is more, they didn't produce current and magnetic field.

This time, the magnet cylinder drop from the al tune is much slower. cause during its fall, it caused flux change which produce current, and current produce magnetic field. Due to the magnetic force, it falls much slower

In this graph, we draw the magnetic and force applied in each tunnel, and we write the flux change in the al tunnel. The reason that magnetic produce electric, and caused emf is when the flux change in the system.

We draw the graph of emf and magnetic field change respect to time. they are both trig function. The reason that the graph looke like this is beacuse during the motion, angle between field and surface changes. Since we applied dot product to determine flux, the change of flux also contains trig function.

Summarize: Magnetic can produce electric due to the change of flux in the field and motion of the wire loop. The emf caused by this is change during the spining of the loop. Electric can also produce magnetic field. Thus, when we do problems that contains both magnetic and electric, we need to consisder both the magnetic force and emf due to their relationship.