Introduction to Circuit Analysis

Course Description:

Introduces the physics of light, periodic and wave motion, electricity and magnetism, and concepts of modern and current physics. Compute key performance parameters in periodic and simple harmonic motion and longitudinal and transverse wave motion, as exemplified by periodic mechanical disturbances, sound, and light. Compute quantities related to light. Solve problems involving the reflection and refraction of light and their applications, including lens and mirror performance and the construction of lenses. Compute effective impedance values for series arrangement and parallel arrangements of resistors, capacitors and inductors and compute time constants for the exponential rise/decay of voltage/current. Solve basic problems in series and parallel alternating and direct current circuits using Ohm’s and Kirchhoff’s laws. Solve basic problems in electromagnetic induction and transformers. Solve basic problems in modern and current physics including (1) the structure of the atom, (2) radioactivity, the associated nuclear reactions, and the concept of half-life, and (3) fission and fusion reactions. Use laboratory equipment to demonstrate scientific principles. Recognize uncertainties in data. Tabulate and graph data and compute results. Work in teams. Draw reasonable conclusions from quantitative data and communicate results to others.

Outcomes:

This was class was a continuation of my introduction to physics principles and thought processes. In one word "amazing".

Sample work:

Lab Report 3

Modern Physics Topics

3/05/2015

Electrical Conduction in the Human Nervous System:

How the topic relates:

Neurons facilitate cell communication in the human nervous system. One of the ways information travels between neurons is in the form of an electrical impulse, called an action potential. According to the authors of Nerve Conduction, electrical synapses let the signal pass unchanged—ion currents flow directly between neurons via gap junctions, allowing the action potential to pass from presynaptic to postsynaptic membranes without delay or loss of signal strength. When the action potential appears in a part of the axon, the voltage change that occurs there causes nearby charges to move toward it or away from it. It is this movement of these charges, i.e. their electrical current, which dictates how fast the action potential travels along the length of the axon. Additionally, in a neuron there are two substances that exhibit electrical resistance: the axoplasm itself and the cell membrane plus myelin sheath, if present. The electrical resistance R along the length of the axon follows the same principles as a wire. So, the speed of communication in the human nervous system is related to voltage, current, and resistance and these three quantities are related through Ohm’s Law V=IR.

Multiple choice questions: Answers in red

1.      What is the conventional direction of current flow?

a.      Positive charge flow.

b.      Negative charge flow.

c.      Bi-directional.

d.      Uni-directional.

2.      Electric current refers to?

a.      Potential difference between two points.

b.      The rate of flow of electric charge.

c.      Coulombs per second.

d.      A and C

e.      All of the above

3.      Resistance is?

a.      Property of a wire or device.

b.      Friction.

c.      Inversely proportional to voltage.

4.      The resistance R of a wire is inversely proportional to?

a.      It’s length.

b.      It’s cross-sectional area.

c.      The material it’s made of.

d.      It’s color.

5.      Does stretching a wire change its resistance?

a.      True

b.      False

Summary:

I chose the topic of the electrical conduction in the human nervous system because I recently took a psychology class and we learned about the human nervous system. I was intrigued by the complexity of the human nervous system, mainly the means of communication and speed. It is amazing how the ions of potassium, sodium and so forth interact to produce potential differences and create electric current. To conclude, I was surprised to learn that capacitance exists in myelinated axons, the myelin sheath contains a membrane that wraps around the axon a couple of hundred times, thus effectively increasing the surface area – the larger the surface area the larger the capacitance!

Reference:

Stewart Meredith, Rodriquez Juan, Thompson Kathryn. “Nerve Conduction” Centenary University. n.d. www.centenary.edu. Web. 5 March. 2015.

Photocopy Machines and Computer Printers:

How the topic relates:

According to Scientific American, In 1938 Chester Carlson developed the xerographic process, which was based on two natural phenomena, materials of opposite electrical charges attract and some materials become better conductors of electricity when exposed to light. Carlson invented a six-step process to transfer an image from one surface to another using these phenomena. First, a photoconductive surface is given a positive electrical charge. The photoconductive surface is then exposed to the image of a document. Because the illuminated sections (the non-image areas) become more conductive, the charge dissipates in the exposed areas. Negatively charged powder spread over the surface adheres through electrostatic attraction to the positively charged image areas. A piece of paper is placed over the powder image and then given a positive charge. The negatively charged powder is attracted to the paper as it is separated from the photoconductor. Finally, heat fuses the powder image to the paper, producing a copy of the original image. This topic relates to what I have learned in class about attraction of particles due to their charge – like particles repel while unlike particles attract. Furthermore, it shows that a transfer of charge is possible thereby changing the charge on a material.

Multiple choice questions: Answers in red

1.      What do like particles do in the presence of each other?

a.      Attract each other.

b.      Repel each other.

2.      An object is negatively charged when?

a.      It is rubbed with a cloth.

b.      It has an excess of electrons.

c.      It has abundance of electrons.

3.      An object is positively charged when?

a.      It has less than its normal number of electrons.

b.      It is a good conductor.

c.      It can readily absorb electrons.

4.      Electric charge is?

a.      Dissipated.

b.      Equally distributed.

c.      Conserved.

5.      The net charge on an object is quantized when?

a.      When the net charge on object is +e or –e times a whole number.

b.      It is zero.

c.      It is a number more than zero.

Reference:

Scientific American. Nature America Inc. “How does a photocopier work?” Scientific American, 31 March 2003. Web. 5 March. 2015.