# Week 15

**Read**: Action-at-a-distance (Chap. 30), the Michelson-Morley experiment (Chap. 34)

**Quiz:**Monday.

**HW**: Foucault and the speed of light (Ex. 30.2), Existence of fields (Ex. 30.3), Relative motion (Ex. 34.3),

**Lab**: Lab clean up and Speed of light calculation (Ex. 31.6). To calculate the speed of light, you will need to re-evaluate your Force between Charges and Force between Currents lab experiments. In particular, you will need to extract epsilon (the electrical permittivity of space) and mu (the magnetic permeability of space) from your previous laboratory data. From these values, you can calculate the speed of light from the formula c^2 = 1 / ( mu * epsilon ). In your lab write-up, you must include (i) a clearly labeled plot of the Coulomb force versus distance (or charge) that includes a curve fit from which you extract epsilon, and (ii) a plot of the magnetic force versus distance (or current) that includes a curve fit from which you extract mu.

**Chapter 30 (6 videos):**

**Chapter 31 (1 videos, watch this to understand how to do this week's laboratory calculations):**

**Chapter 34 (no videos yet…):**

Optional:

Optional:

Here is a wonderful little video produced by Veritasium on how electrical energy is transmitted through power lines.