AP Physics 2 Cram Mode Unit 2-4

2nd Law of Thermodynamics

In an isolated system, entropy (state of disorderedness) can only stay constant or increase

Equipotential Lines

Equipotential Lines are always perpendicular to Field Lines

Equipotential Lines in a Capacitor

Always horizontal

Equipotential Lines

Lines of equal electrical potential, meaning no work must be done

Internal Resistance in Wires

Wires have internal resistance (experimental FRQ)

Voltage Current Relations in circuits

Current is not used up in a circuit, Voltage is

Current in Circuits

Current is not split up evenly between junctions and is dependent on the path of least resistance

Capacitor Charging Behavior

Uncharged capacitors act like short circuits,initially all current goes to the uncharged capacitor

Charged Capacitor Behavior

No more current flows through the branch after the capacitor is charged and the voltage of the capacitor is equal to the battery

qvBsinTheta

for a positive charge, v is on the thumb, B is on the index finger, and middle finger is the magnetic force.

Theta is the angle between angle between the field and velocity

Reverse thumb if charge is negative

Magnetic Field from Current Carrying Wire

Thumb in the direction of Current, with magnetic field curling in the direction of it. Vice versa

RHR #3 BILsintheta

Current on Thumb, Field on Pointer, Force on middle finger

Theta is the angle between B and L

Changing Magnetic Flux

Induced current opposes the change in magnetic flux