Homework Help: Electricity and Magnetism

1. Jan 4, 2005

JimmyRay

Hi my grade 11 physics class is on its final unit (Electricity and Magnetism) and I am a little lost...... So far we are doing Charge and Voltage (we learned the formulas)... and we're expected to know that circuit diagram stuff and Ohm's Law? lol a bunch of stuff we were suppose to learn in grade nine...

I was just wondering if you guys could provide me with a website or something which would help review some grade 9 electricity material or even some grade 11 stuff... I kind of don't understand the concepts (charge, voltage, current!!), I know it seems easy but I guess I didnt really learn it well in grade 9. I can do the math but I won't understand what it all means, lol.

We are going to use what we learn and apply it to circuit analysis..........I just want a better understanding any help would be appreciated.

thanks.

2. Jan 4, 2005

3. Jan 5, 2005

JimmyRay

Wow..... I just spent like 2 hours reading a bunch of stuff on that site. That helps out a LOT on understanding the concepts related to this unit. It also somewhat confused me... The parts about electromagnetics...... and CHARGE was harrrddd to understand, I think I sort of got it now...

But I have a few questions...

Is charge just electrons and protons? Because in the website it said charge was a step below the atoms........and it was a substance...

Voltage is the electric field which surrounds all matter. Right? We measure it by seeing voltage between two distances? But not an object's actual voltage?

4. Jan 5, 2005

da_willem

charge is a property of particles. It only comes in discrete amounts. The smallest amount is called the elementary charge and is the charge of a proton, approximately 1.6E-19 Coulombs. The charge of the electron is minus this amount of charge. But there are many more types of particles that 'carry' (figurely speaking) charge.

Not really. The electric field is the difference in voltage (the word used by most physicists is potential). All physically measurable phenomena involve only differences in this electric potential, so the potential reallu has no meaning as an absolute quantity. It is only a mathematical trick to make life easier, but at the end of a calculation you are only interested in potential differences (wich are physically measurable).