What do you expect to happen to the field as you get really far from the rod? $$E_x = \dfrac{\lambda}{4\pi\varepsilon_0\}\dfrac{L}{x\sqrt{x^2+L^2}}$$ 1. $E_x$ goes to 0. 2. $E_x$ begins to look like a point charge. 3. $E_x$ goes to $\infty$. 4. More than one of these is true. 5. I can't tell what should happen to $E_x$. Note: CORRECT ANSWER: D (A and B)

I spent ... hours on the second homework. 1. 1-2 2. 3-4 3. 5-6 4. 7-8 5. More than 9

I felt ... doing the Python part of the homework. 1. relatively comfortable 2. comfortable enough 3. kind of uncomfortable 4. really uncomfortable 5. I didn't do it

## Announcements * Will start "counting" clickers next Monday - Register your clicker! * If you need help with Python, let me know ASAP! * Honors Option - Talk to me about your ideas - Option 1: Design a computational activity for this class - Option 2: Develop a computational model and paper for an interesting electrostatics phenomenon - Option 3: Pitch me your idea

Taylor Series? 1. I remember those and am comfortable with them. 2. I rememeber them, but it might take a little while to get comfrtable. 3. I've definitely worked with them before, but I don't recall them. 4. I have never seen them.

Given the location of the little bit of charge ($dq$), what is $|\vec{\mathfrak{R}}|$? <img src ="./images/sphereintegrate.png" align="left" style="width: 300px";/> 1. $\sqrt{z^2+r'^2}$ 2. $\sqrt{z^2+r'^2-2zr'\cos\theta}$ 3. $\sqrt{z^2+r'^2+2zr'\cos\theta}$ 4. Something else Note: CORRECT ANSWER: B

Which of the following are vectors? (I) Electric field, (II) Electric flux, and/or (III) Electric charge 1. I only 2. I and II only 3. I and III only 4. II and III only 5. I, II, and II Note: * CORRECT ANSWER: A

## Gauss' Law <img src="./images/gauss_pt_charge.png" align="center" style="width: 350px";/> $$\oint_S \mathbf{E}\cdot d\mathbf{A} = \int_V \dfrac{\rho}{\varepsilon_0}d\tau$$