PH221 - LAB - Assignment 5-8

- Lab 4 Review textbook Chapter 19 which involves the vector characteristics of a moving charged object

within a charged parallel plate capacitor. This simulation can be downloaded from within your course

under “PH221 Simulations”; its file name is “#15 Charge and Cap.ip”. A positively charged particle is

moving horizontally when it enters the region between the plates of a capacitor as the simulation

illustrates. (a) Draw (sketch) the trajectory that the particle follows in moving through the capacitor. (b)

When the particle is within the capacitor, which of the following four vectors, if any are parallel (||) to

the electric field E inside the capacitor: the particle’s displacement (), its velocity (v), its linear

momentum (p), and its acceleration (a)? For each vector, explain why the vector is or is not parallel to

the electric field of the capacitor.

- Run the simulation noting the particle’s trajectory (as indicated by the “tracking” or “strobes”) while

inside the capacitor cavity. Also note the velocity and acceleration vector, v and A, respectively arrows.

Fill in the answers for the blanks in the Lab Answer Sheet at the end of this lab.

A capacitor is a charge storage device. A parallel plate capacitor consists of parallel conducting plates

separated by an insulator. In this experiment, the insulator is air and there is equal but opposite charges

(+Q and –Q) placed on each conducting plate (See Figure 18.25, Section 18.6 and 18.7 in your textbook).

This virtual lab investigates the effects (if any) of a positively charged particle midway between the

oppositely charged plates of a parallel plate capacitor moving in a + x-direction. Just as in Lab 3, there

will exist an electrostatic (Coulomb) force on the charged particle when it is inside the capacitor.

In this lab, you will investigate electric field (E) lines. Electric charges create an electric field in space

surrounding them. Electric field lines essentially give us a “map” of the direction and strength

(magnitude) of the E field at various places in space. E lines are always directed away from positive

charges and toward negative charges (see Figure 18.23, textbook Section 18.7, and Lesson 3). In Figure

18.27 the absence of E lines indicates that the electric field is relatively weak between the two positive

charges. Since you will be performing in this experiment a virtual mapping of E lines for a certain charge

distribution, carefully study Conceptual Example 13 (“Drawing Electric Field Lines”) for the dos and

don’ts of mapping E field lines.

Electric Field Lines Mapping Rules

-The E lines do not cross each other

-The closer the lines are together, the stronger the E in that region

-The field lines indicate the direction of E; the field points in the direction tangent to the field line at any

point

-The lines are drawn so that the magnitude of the electric field, |E|, is proportional to the number of

lines crossing unit area perpendicular to the lines. The closer the lines, the stronger the field

-E lines start on + charges and end on - charges; the number starting or ending is proportional to the

magnitude of the charge.

Lab 5 Introduction

Lab 5 – The Critical Angle Due at the end of Week 5

This week’s lab is based on our knowledge of Snell’s Law:

n1 sin q1 = n2 sin q2

and subsequently the critical angle:

sin qc = nr/ni

Imagine light traveling in these three situations:

Air to water (nwater = 1.33)

Air to glass (nglass = 1.49)

And

Water to glass.

Please make a plot of angle of refraction versus incident angle for each of these and please point out

where the critical angle is.

Please remember to do the full report here and remember this assignment is due at the end of week 5.

Lab 6 Introduction

Lab 6 – Wave Function and it Probability Due at the end of Week 6

The key part of this week is looking at wave functions and what they mean.

The wave function is used to determine various properties in physics. One of them is the probability of

where a particle (usually an electron) is at one point in time. So let’s look at the wave function for the

infinite square well. This is given as:

Where L is the width of the well, x is the position and n is the integer order of the wave function. So

please plot this and |ψ|2 for n = 1, 2 and 3 and see if there is correlation here between the values.

At what points do they connect here?

Construction Point: Use Excel to make these plots and for simplicity let L = 1 and then run x from 0 to 1

in steps of 0.05.

Lab 7 – Radioactivity Due at the end of Week 7

Radioactive decay is a very useful tool in physics and has many real world applications. So what you are

going to do this week is look at a plot of a radioactive decay and determines time lines and eventually

the isotope in question.

This sample started with 1000 particles on the y axis and with time and the x axis.

1) Determine the half-life of this isotope using the equation where t is the half-life.

2) Determine how many particles are present at 4000, 6000, 8000 and 10000 years using the graph

and the equation.

3) What are some applications of an isotope like this?

4) Once you have the half-life, what do you think this isotope is?

Lab 8 – Reactors Due at the end of Week 8

This week’s Lab will be a little different. Since we are focusing on nuclear reactors and their uses, please

write a 2 page research paper on the major different types of nuclear reactors. Be sure to include ones

inside and outside the United States. Make sure to include the basic operations and also include

problems that have affected these and any solutions that were used to solve these problems. You do

not have to follow the report format here, just follow the usual APA format here.

REPORTS

Title Page: Center the following information on the title page: Course, title of the lab, the experiment

number, your name and the date you performed the experiment.

0

100

200

300

400

500

600

700

800

900

1000

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000

Particle Number vs. Time (Years)

Introduction: In this section you describe the objectives and concepts of the lab. Define any key words,

show any equations you use in the lab, and describe any theory or law that is used. Do no describe the

procedures of the experiment or copy the objectives from the handout. The introduction should be no

shorter than 1/2 page in length.

Procedure: You will have this section only if modification or changes are made in the experiment. If this

is the case, you will need to describe how the experiment was modified.

Data: The measurements and observations you make must be recorded in neatly prepared data

tables. You can use the examples that are provided for you in the experiment.

Results and sample calculations: Raw data collected is to be manipulated in this section. This normally

involves calculating quantities using relevant equations. When calculating a quantity, the calculation

must be shown step by step. This is to indicate to me that you are performing the correct

procedure. Further calculation of the same quantity need not be shown unless it requires the use of a

different equation. For example, for the first experiment, you should also calculate the resultant

vector and show it does or does not match the value obtained from experiment.

You may need to construct neat tables top place your calculated quantities. Use a spreadsheet. Often

the results of an experiment must be presented graphically. Graphs are to be plotted on the computer

and include gridlines. When plotting a graph, chose a scale that is a multiple of 1, 2, 5, or 10. The

computer usually does this for you. The graph must have a title indicating the quantities represented,

the X and Y axis properly labeled with the quantity and units, and the best straight line or curve drawn

through the data points. The curve or line must take up most of the space allotted for the graph. The

graph must be large enough to extract data from it. If you have a straight line, include the equation and

the correlation coefficient (r-squared).

Frequently, you will need to do something with data in order to put it into useful form. This may include

answering questions, doing arithmetic or algebra, completing tables, or making graphs. A sample

calculation must be included in the lab report, even if you use a calculator or spreadsheet. In addition,

you must give all measured and calculated values some form of physical units. These values must be

labeled appropriately.