Mod 4: Electricity and Magnetism

• E=V/d, where E is electrical field strength, V is voltage and d is distance.
• E=F/Q, Where E is electric field strength, F is force, and Q is charge.
• V/d = F/Q
• To find Force: q1*q2/4πε*r^2
• ε = 8.854*10^-12
• The head of the arrow always means a negative charge. The closer the arrows, the denser the fields, the higher the electric field strength.
• Voltmeters can only be connected in parallel, Ammeters can only be connected in series.
• Charge by Induction: two objects do not touch eachother

  Charge by contact: two objects touch eachother

  Charge by friction: two objects are rubbed against swapping electrons
• Kirchoff's law of current:

  Current in= Current out

  Kirchoff's law of voltage:

  voltage in = voltage out
• Voltage should be on the y-axis and current should be on the x axis for ohmic/non-ohmic resistors. If this is not the case, then, 1/r=I/V
• non-ohmic resistors always have a non-linear exponential/logarithmic looking graph.
• I coulomb = 6.25 x 10^18 electrons