P114-Morning –Summer’07

Extra Credit #2

Due August 8, 2007

Team #____________

Member #1_____________________

Member #2_____________________

Member #3_____________________

Rules:

-Collaborations between team members are encouraged; however one or two authors will be responsible for one problem and may be asked to explain it.

-The authors should present the solution on a blank sheet with their names on it. Submissions from a same team should be stapled together

-Solutions should include “self-explained” diagrams/sketches, with minimal wording. Neat presentation will count toward the problem grading.

1.- Conductivity of solutions: in the experiment shown below, which solution would give the brightest light? Order them from brightest to dimmest: tap water, distill water, water with dissolved sugar, water with dissolved salt, water with vinegar. Include a detailed explanation using the terminologies we have introduced related to electricity.

2.- Electron momentum: Electrons have mass, describe an experiment that would visually confirm that electrons in motion can transfer momentum to physical objects such as a wheel with paddles.

3.- Magnetic force: describe what happens if a magnet is placed close to a transparent light bulb (such that you can se the thin resistance inside) a)if the bulb is powered a DC battery (flash light) b)if it is powered by an AC (alternating current) outlet. AC changes direction 60 times per second or its frequency is 60Hz.