Physics 397 * Physics of Modern Devices * Spring 2007

Introduction

Homework counts 30% towards your course grade. For submission and grading of homework we will often use an Internet-based homework service called WebAssign. It has several advantages:

• You submit your homework assignment on the Web, and you get it graded immediately, instead of turning it in to an instructor and waiting a week to get it back.
• If any of your answers were wrong, you can retry the incorrect problems and resubmit your assignment. You are allowed up to 2 submissions.
• Although every student is assigned the same problems, the numbers in each problem are randomized so that the numerical answer may vary from student to student.

Getting Started with WebAssign

Although you can log into WebAssign and examine the homework assignments right away, you won't be able to submit answers until you register your WebAssign access code. You can purchase an access code (often called WebAssign Card) from the cashiers at either the Rutgers University Bookstore or the Cook/Douglass Cooperative Bookstore, or you can buy it online. Make sure you purchase the WebAssign code to be used for the textbook How things work by Louis A. Bloomfield.

To begin using WebAssign, go to the WebAssign Login page. (There is a link to this login page from our main course home page). For your username enter the first letter of your last name in lowercase, followed by the ALL 9 DIGITS of your Rutgers Student ID number.

For the institution, enter rutgers in lowercase, i.e. don't capitalize rutgers. For the password, enter your 9-digit Rutgers Student ID number including leading zeroes if any. After you have logged in, you can (and undoubtedly should) change your password, but you cannot change your username or institution.

If you are unable to get into WebAssign for any reason, send email to me.

If you used webassign before and your ID does not work as the password, try your old password. (Normally old passwords are reset for each semester). If that still doesn't work (or you've forgotten your old password), email me immediately.

As mentioned before, the first time you use webassign you must register your access code. You can buy the access card separately at the bookstore or online at the WebAssign website (online you will need a credit card). Make sure that you ask for the correct WebAssign card. After the 14 day grace period has expired, you will not be allowed any longer to view nor download the assignments, until you register your access code.

If you are registered for more than one class using WebAssign, the WebAssign page will give you a list and let you select the class to work on. If you do not see all classes, it usually means you have different usernames in the different classes. Contact your instructor immediately to correct this.

Changing your password and/or email address

As mentioned above, your initial password is your 9-digit ID number. Your email address in WebAssign is your eden account address. If you wish to change either of these, just log into WebAssign and click the Options button located near the top right, just below the Logout button. That will take you to a page with buttons for changing password or email address.

After changing your password or email address, BE SURE TO CLICK THE SAVE BUTTON or else the change won't be made.

Preparing Homework Assignments

Each assignment due date will be announced in class and clearly indicated on WebAssign. WebAssign enforces this deadline very strictly, and won't accept a submission if you are even one second late.

The lectures each week will give you practice in doing problems similar to the ones in the assignment. You are encouraged to discuss homework problems with your classmates, and the Math and Science Learning Center would be an excellent place for you and your friends to work together. Of course you should attempt the problems on your own before discussing them with your friends. If you simply copy someone else's method for solving a problem, you will not have learned it well enough for success on the in-class quizzes.

When you are ready to submit an assignment, note that you can enter numerical answers in a variety of formats:

1. A number, with or without a decimal point, e.g. 3215 or 1.23 is a correct format. DO NOT use commas e.g. 3,215 will not be accepted.
2. In scientific notation, e.g. 1.23E5 which means 1.23 multiplied by 10 raised to the power 5. So 1.23E5 is the same as 123000. DO NOT leave a space between the E and the number before or after it. Also, DO NOT use the notation 10^5 or 10**5 to express 10 to the fifth power.
3. Your answer can make use of mathematical operators like +, -, *(multiply), the slash symbol (/) for division, and parentheses. So one could enter 3*(6+5) which equals 33. DO NOT leave spaces between numbers and operators, and DO NOT include equal signs, e.g. =3/6 is invalid.
4. THE MOST COMMON PITFALL FOR STUDENTS is that WebAssign only counts an answer as correct if it is within 1% of the right answer. So in solving a homework problem, you should NOT round off any numbers until the very end, and then you should submit the answer to three significant figures. For example, if your answer is 0.012345, you should enter it as 0.0123 or 1.23E-2. If you enter it as 0.012, you will be marked wrong, because 0.012 differs from 0.0123 by well over 1%. Note that leading zeros are NOT significant figures which means that 0.012 has only two significant figures.
5. Be careful NOT to use the letter O for zero 0 or the letter l for the number one 1. You cannot enter "pi" for 3.14159.

Submitting Homework Assignments

Once you've entered your answers, click the "Submit for grading" button at the bottom of the assignment. Your assignment will be returned with answers marked correct (with a check) or incorrect (with an X). If any were incorrect, you can retry the assignment. When you are ready to resubmit, click the "Review Last Submission" button. This will bring up all previous answers and allow you to edit the incorrect answers. If you simply call up the assignment, all answers are taken as blank again, and you will need to re-enter all your previous correct answers.

You are also allowed to "Submit" your answer separately for each question. This may be a useful shortcut.

1. Once you click the Submit button, be patient and WAIT for a reply. If you impatiently click the button again, you will use up another of your 2 allowed submissions.
2. You must allow your Web browser to accept cookies. Most Web browsers do accept cookies by default, so you should be okay unless you have explicitly disabled this feature.
3. If you do not see your name at the top of the assignment, you are not logged in properly. This usually results from bookmarking an internal WebAssign page instead of the login page.
4. Do not use the "Back" button on your browser; use the buttons on the WebAssign screen. Otherwise you may recall a cached page and your assignment might not get submitted properly.
5. Be sure to click the WebAssign logout button before exiting your browser.