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physics/Electric Force, Field, and Potential/Capacitors.md

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+[[Electric Force, Field, and Potential]]
+# Summary
+* Measured in capacitance ($C=\frac{Q}{\Delta V}$), value fixed by physical build $C=\kappa \epsilon_0\frac{A}{d}$
+* Field between plates is uniform except near edges. $E_C=\frac{Q}{\kappa \epsilon_0 A}$ (equal to $\frac{\Delta V}{d}$)
+* Charged particle between plates feels constant force. Projectile with constant accel.
+* Stored energy written as: $U_C=\frac{1}{2}Q\Delta V=\frac{1}{2}C(\Delta V)^2=\frac{Q^2}{2C}$.
+* Adding dielectric raises capacitance by factor of $\kappa$, sets up induced field inside dielectric that opposes plate field.
+* On AP exam, only parallel plate capacitors required, edge effects ignored unless stated otherwise.

physics/Electric Force, Field, and Potential/Conservation of Electric Energy.md

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+[[Electric Force, Field, and Potential]]
+# Summary
+* Change in electric potential energy for charge moving between 2 potentials $\Delta U_E=q\Delta V$ (J)
+* q can be positive or negative. $\Delta V=V_{final}-V_{initial}$.
+* Energy is conserved: $\Delta K=-\Delta U_E$
+* Positive charges speed up moving towards lower potential. Negative charges speed up moving towards higher potential.
+* Electric field points towards decreasing potential.
+* For particle starting at rest, kinetic energy gained equals magnitude of $q\Delta V$, lets you solve for final speed.

physics/Electric Force, Field, and Potential/Electric Charge and Electric Force.md

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+[[Electric Force, Field, and Potential]]
+# Summary
+* Charge is quantized, integer multiple of $e=1.6x10^{-19}$.
+* $q=\pm ne$
+* Coulomb's law: $F=k\frac{p_1p_2}{n^2}$; directly proportional to charge, inversely proportional to distance.
+* Same signs repel, opposite signs attract.
+* Electric force is stronger than gravity for tiny particles, gravity controls large scale because big objects are usually neutral.
+* Electric permittivity measures how much a material polarizes in a field. Conductors let charge move freely, insulators don't.
+* Only need to calculate force for 4 or less interacting charges unless situation is highly symmetrical.

physics/Electric Force, Field, and Potential/Electric Fields.md

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+[[Electric Force, Field, and Potential]]
+# Summary
+* Electric field at a point = electric force on a positive test charge divided by charge = $\vec E=\frac{\vec F_E}{q}$ (unit N/C).
+* Test charge's impact on field is negligible.
+* Field lines point towards negative and away from positive. Closer lines = stronger field.
+* Net field from several charges is sum of vectors.
+* Inside a conductor in electrostatic equilibrium field is zero. Charge sits on surface, surface field is perpendicular to surface.
+* Inside a charged insulator inside can be nonzero since charge stays instead of moving to surface.

physics/Electric Force, Field, and Potential/Electric Potential Energy.md

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+[[Electric Force, Field, and Potential]]
+# Summary
+* Electric potential energy is work required from external force to assemble charges from infinity. Infinity set is the zero reference.
+* Elastic potential energy: $U_E=\frac{1}{4\pi \epsilon_0}\frac{q_1q_2}{r}=k\frac{q_1q_2}{r}$
+* Positive $U_E$ means repulsive interaction from like charges.
+* Negative $U_E$ means attractive interaction from unlike charges.
+* For multiple charges, add potential energy of each pair.
+* $U_E$ is a scalar.
+* Energy is conserved, as charges move potential is traded for kinetic.

physics/Electric Force, Field, and Potential/Electric Potential.md

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+[[Electric Force, Field, and Potential]]
+# Summary
+* Electric potential is energy per charge: $V=\Delta U_E/q$ (Volts)
+* Potential comes from multiple point charges added as scalars.
+* Potential can be positive or negative, reference set at infinity.
+* Electric field points towards decreasing potential. $|\vec E|=|\Delta V/\Delta r|$
+* Equipotent lines (isolines) are perpendicular to field vectors. No work is done moving charge along equipotent.
+* Conductors in electrical contact redistribute charge on the surface until it sits at the same potential.

physics/Electric Force, Field, and Potential/The Process of Charging.md

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+[[Electric Force, Field, and Potential]]
+# Summary
+* Net charge changes only when charge travels in and out of a system.
+* Charging usually happens through electron transfer.
+* Induced charge separation polarizes an object without contact. Happens in neutral conductors and insulators.
+* In conservation problems, charge of separated objects should sum to charge of system.
+* Grounding occurs when a system connects to a large neutral object.
+* Conductors let electrons move easily, insulators only let bound charges shift slightly.
+* Main 3 ways to charge: friction induction contact.