# Review of all Electricity and Magnetism Dimensions – AP Physics C

Bo: Hey guys. Billy: Hey Bo. Bobby: Hi Bo. ♫ (lyrics) Flipping Physics ♫ Mr. P.: Ladies and gentle people, the bell has rung, therefore class has begun. Therefore you should
be seated in your seat and ready to review electricity and magnetism dimensions, because dimensions are your? Billy, Bobby, Bo: Friends. Mr. P.: That’s right.
Dimensions are your friends. Here we go. Bobby, what are the symbol and dimensions for charge? Bobby: The symbol for charge is Q. Generally, a lowercase
q for a point charge, or for a portion of a charge, and an uppercase Q for a whole charge, and the dimensions for
charge are coulombs, or capital C. Mr. P.: Billy, is coulomb
a base SI dimension? Billy: No, coulombs are
not a base SI dimension. Mr. P.: Bo, what are the
symbol and dimensions for electric field? Bo: The symbol for electric
field is an upper case E, and the dimensions are newtons per coulomb or volts per meter; however, we haven’t defined volts yet. Mr. P.: True. Billy, for
what is the volt a dimension? Billy: The volt is, uh, is the dimension for electric
potential difference, and the symbol for electric potential difference is delta V. Oh, and we should also know that a volt is a joule per coulomb. Mr. P.: Bo, what are
the symbol and dimension for electric flux? Bo: Electric flux. The symbol is that weird uppercase phi, which looks like an uppercase
I with a circle in it and a subscript of an uppercase E, to identify it as electric flux. Oh, and the dimensions
for electric flux are newtons times meters
squared over coulombs, or just volts times meters. Mr. P.: Very nice, Bo. Bobby, what are the symbol and dimensions for capacitance? Bobby: The symbol for capacitance is an uppercase C, and its dimensions are farads, and a farad is a coulomb per volt, which reminds me that we shouldn’t confuse the symbol of our capacitance, with an uppercase C, with the dimensions for a charge, coulombs, which is also, unfortunately, an uppercase C. Mr. P.: Billy, what are
the symbol and dimensions for current? Billy: The symbol for
current is an uppercase I, and its dimensions are amperes, or amps, which is a coulomb per second, and it is amperes which are
the base SI dimension, and not coulombs. Mr. P.: Bobby, what are the dimensions for resistance? Bobby: The dimensions
for resistance are ohms, and the symbol for an ohm is an upside-down horseshoe, and I know it’s upside-down, because all the luck has fallen out of it. Billy: And it can’t
hold soup, for example. Bobby: Yes, it can’t hold soup, which I guess is unlucky. Oh, and an ohm is a volt per amp. Mr. P.: Yes, I’m (laughs)
I’m glad you remember. Bo, what are the symbol and dimensions for resistivity? Bo: The symbol for resistivity
is a lowercase rho, which looks like a curly lowercase P, and shouldn’t be confused with volumetric mass or charge density, even though it uses the exact same symbol. The dimensions for
resistivity are ohm meters. Mr. P.: What is the difference between resistance and resistivity? Billy? Billy: Resistivity is a material property, and resistance is for a specific object, and it depends on its material and its geometric shape. Mr. P.: Bobby, what are
the dimensions and symbol for the time constant? Bobby: The symbol for the time constant is a lowercase tau, not to be confused with torque, which has the same symbol, and the dimensions for the time constant are seconds. Mr. P.: Billy, what are
the symbol and dimensions for magnetic field? Billy: The symbol for
magnetic field is a B, and its dimensions are teslas. Mr. P.: Bo, what is a tesla? Bo: A tesla? It’s a newton divided
by the quantity of amps times meters. Mr. P.: And what are the
symbol and dimensions for magnetic flux? Billy? Billy: Magnetic flux uses the same symbol as electric flux, only with a capital B, instead of a capital E, as a subscript, and the dimensions for magnetic flux are webers, eh, or Wb. Mr. P.: And, Bobby, what is a weber? Bobby: A weber is a tesla
times a meter squared. Mr. P.: Bo, what are the
symbol and dimensions for inductance? Bo: The symbol for inductance is an uppercase L, not to be confused with angular momentum, and its dimensions are henries, and a henry is a volt-second per amp. Mr. P.: Good job, everybody. You guys have learned really well. One last time, dimensions are your? Billy, Bobby, Bo: Friends. Mr. P.: Thank you very much for learning with me today. I enjoyed learning with you. Voiceover: Lecture notes are available at FlippingPhysics.com Please enjoy lecture notes responsibly. (man on swing yelling
in forward and reverse)

## 2 thoughts on “Review of all Electricity and Magnetism Dimensions – AP Physics C”

1. deedsth says:

very nice!

2. foosion says:

Your the reason I failed physics -ken