Find out about electromagnetism and how it works.
Sunday, March 30, 2014
Wednesday, March 26, 2014
MAGNETISM HW
Some questions for research:
1. What exactly is a compass?
2. Where is "magnetic north" on Earth? Magnetic south?
Yet more things to think about:
3. Must there always be at least one north pole with every south pole (and vice versa)? Can magnetic monopoles exist? This is not something you'd necessarily know, so feel free to research.
4. How are magnetic fields different from electric fields?
1. What exactly is a compass?
2. Where is "magnetic north" on Earth? Magnetic south?
Yet more things to think about:
3. Must there always be at least one north pole with every south pole (and vice versa)? Can magnetic monopoles exist? This is not something you'd necessarily know, so feel free to research.
4. How are magnetic fields different from electric fields?
Saturday, March 8, 2014
Test practice
1. Consider three resistors: 2, 6 and 4 ohms, connected in series to a 36 volt battery. Find the total resistance, current and all voltages.
2. Repeat the above problem, if the resistors are in parallel with the 36 volt battery.
3. Charge review. Consider a chunk of charge: -15 C.
A. What kind of particles are these?
B. How many of these particles are there
C. If a 10 C charge is brought nearby, 0.1 m away, what is the force between the two chunks of charge?
D. Draw the electric field between the charges.
Wednesday, March 5, 2014
Test heads-up
Test on circuits (and earlier charge stuff) is next Friday, right before spring break. Sorry for the final push - cant be helped.
Tuesday, March 4, 2014
The birthday problem revisited
So, I misspoke in class about the birthday problem. The probability that gets so large so quickly is that there will be ANY two people in the group with the same birthday. NOT that Atira (for example) will find someone in a group that shares her birthday.
That's a pretty big difference and I didn't mean to misrepresent it. Giant OOPS! Sorry! Here's the gist of it, followed by the reference:
In probability theory, the birthday problem or birthday paradox[1] concerns the probability that, in a set of n randomlychosen people, some pair of them will have the same birthday. By the pigeonhole principle, the probability reaches 100% when the number of people reaches 367 (since there are 366 possible birthdays, including February 29). However, 99.9% probability is reached with just 70 people, and 50% probability with 23 people
http://en.wikipedia.org/wiki/Birthday_problem
That's a pretty big difference and I didn't mean to misrepresent it. Giant OOPS! Sorry! Here's the gist of it, followed by the reference:
In probability theory, the birthday problem or birthday paradox[1] concerns the probability that, in a set of n randomlychosen people, some pair of them will have the same birthday. By the pigeonhole principle, the probability reaches 100% when the number of people reaches 367 (since there are 366 possible birthdays, including February 29). However, 99.9% probability is reached with just 70 people, and 50% probability with 23 people
http://en.wikipedia.org/wiki/Birthday_problem
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