AP Physics 2 Flashcards: Electric Fields

What this deck covers

This deck focuses on Electric Fields, giving you a quick way to review the definitions, rules, and examples that matter most for AP Physics 2.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: Explain the change in electric field strength if the charge is tripled.

Answer: Field strength is tripled. Field strength is directly proportional to the source charge magnitude.

Flashcard 2: State the formula for the electric field between two parallel plates.

Answer: $E = \frac{V}{d}$. Uniform field between plates equals voltage divided by separation.

Flashcard 3: What is the electric field due to a charge distribution at infinity?

Answer: Zero. Field approaches zero as distance approaches infinity for finite charges.

Flashcard 4: What is the effect of a conductor on the external electric field?

Answer: Distorts and reduces the field inside. Conductor redistributes charges and creates field-free interior region.

Flashcard 5: What is the direction of the electric field due to a negative point charge?

Answer: Radially inward towards the charge. Electric field points toward negative charges in all directions.

Flashcard 6: What is the charge of an electron?

Answer: $-1.6 \times 10^{-19}$ C. Elementary negative charge magnitude in coulombs.

Flashcard 7: Explain the change in electric field strength if the charge is tripled.

Answer: Field strength is tripled. Field strength is directly proportional to the source charge magnitude.

Flashcard 8: How does the electric field between parallel plates depend on the area of the plates?

Answer: Field is independent of the plate area. Field depends only on charge density and plate separation, not area.

Flashcard 9: What is the electric field inside a conductor in electrostatic equilibrium?

Answer: Zero. Free charges redistribute to cancel internal fields in equilibrium.

Flashcard 10: What happens to the electric field if the distance from a point charge is doubled?

Answer: Field strength decreases by a factor of 4. Inverse square relationship: doubling distance quarters the field strength.

Flashcard 11: State Gauss's law for electric fields.

Answer: $\oint E \cdot dA = \frac{Q_{enclosed}}{\varepsilon_0}$. Fundamental relationship between electric flux and enclosed charge.

Flashcard 12: Determine the net electric field at a point equidistant from two equal charges.

Answer: Zero, if charges are opposite. Equal magnitudes but opposite directions cancel when charges are opposite.

Flashcard 13: What is the direction of electric field lines around a dipole?

Answer: From positive to negative charge. Field lines exit positive charges and enter negative charges.

Flashcard 14: What is the electric field at the surface of a conductor?

Answer: Perpendicular to the surface. Electric field must be normal to conductor surface in equilibrium.

Flashcard 15: What is the electric field due to a charge distribution at infinity?

Answer: Zero. Field approaches zero as distance approaches infinity for finite charges.

Flashcard 16: What is the electric field inside a conductor in electrostatic equilibrium?

Answer: Zero. Free charges redistribute to cancel internal fields in equilibrium.

Flashcard 17: Which principle explains the behavior of electric fields in superposition?

Answer: Principle of superposition. Vector addition of individual field contributions from multiple sources.

Flashcard 18: What is the effect of a grounded conductor on nearby electric field lines?

Answer: Field lines terminate on the conductor. Grounded conductors provide discharge path, terminating field lines.

Flashcard 19: What is the charge of an electron?

Answer: $-1.6 \times 10^{-19}$ C. Elementary negative charge magnitude in coulombs.

Flashcard 20: What is the direction of the electric field due to a negative point charge?

Answer: Radially inward towards the charge. Electric field points toward negative charges in all directions.

Flashcard 21: What is the effect of a conductor on the external electric field?

Answer: Distorts and reduces the field inside. Conductor redistributes charges and creates field-free interior region.

Flashcard 22: What is the electric field at the surface of a conductor?

Answer: Perpendicular to the surface. Electric field must be normal to conductor surface in equilibrium.

Flashcard 23: What is the effect of a grounded conductor on nearby electric field lines?

Answer: Field lines terminate on the conductor. Grounded conductors provide discharge path, terminating field lines.

Flashcard 24: State Coulomb's law in terms of force between two point charges.

Answer: $F = \frac{k |q_1 q_2|}{r^2}$. Force between charges depends on product of charges and inverse square of distance.

Flashcard 25: What is the value of the electric constant $k$ in vacuum?

Answer: $k = 8.99 \times 10^9 \text{ N m}^2/\text{C}^2$. Standard value for the proportionality constant in vacuum.

Flashcard 26: State Gauss's law for electric fields.

Answer: $\oint E \cdot dA = \frac{Q_{enclosed}}{\varepsilon_0}$. Fundamental relationship between electric flux and enclosed charge.

Flashcard 27: State the unit of electric field strength in the SI system.

Answer: Newton per coulomb (N/C). Standard SI unit combining force (N) per unit charge (C).

Flashcard 28: What is the effect of doubling the distance between a charge and a point in the field?

Answer: Electric field decreases by a factor of 4. Inverse square law: field strength decreases by factor of four.

Flashcard 29: Identify the direction of the electric field around a positive point charge.

Answer: Radially outward from the charge. Electric field points away from positive charges in all directions.

Flashcard 30: State the formula for the electric field between two parallel plates.

Answer: $E = \frac{V}{d}$. Uniform field between plates equals voltage divided by separation.

Flashcard 31: What is the formula for the electric field due to a point charge?

Answer: $E = \frac{kQ}{r^2}$. Coulomb's law applied to field strength, where $k$ is the electric constant.

Flashcard 32: Determine the electric field inside a hollow charged spherical conductor.

Answer: Zero. No charges inside hollow conductor means zero internal field.

Flashcard 33: What is the effect of doubling the distance between a charge and a point in the field?

Answer: Electric field decreases by a factor of 4. Inverse square law: field strength decreases by factor of four.

Flashcard 34: What is the relation between electric field and electric potential?

Answer: $E = -\frac{dV}{dx}$. Field is the negative gradient of potential in one dimension.

Flashcard 35: Define an electric dipole.

Answer: Two equal and opposite charges separated by a distance. Basic configuration creating electric dipole moment and field pattern.

Flashcard 36: What happens to the electric field if the distance from a point charge is doubled?

Answer: Field strength decreases by a factor of 4. Inverse square relationship: doubling distance quarters the field strength.

Flashcard 37: State Coulomb's law in terms of force between two point charges.

Answer: $F = \frac{k |q_1 q_2|}{r^2}$. Force between charges depends on product of charges and inverse square of distance.

Flashcard 38: What is the direction of electric field lines around a dipole?

Answer: From positive to negative charge. Field lines exit positive charges and enter negative charges.

Flashcard 39: What is the effect of introducing a dielectric in a parallel plate capacitor?

Answer: Reduces the electric field. Dielectric materials decrease field strength by polarization effects.

Flashcard 40: Identify the electric field at the center of a uniformly charged ring.

Answer: Zero. Symmetry causes all field contributions to cancel at the center.

Flashcard 41: Determine the net electric field at a point equidistant from two equal charges.

Answer: Zero, if charges are opposite. Equal magnitudes but opposite directions cancel when charges are opposite.

Flashcard 42: What is the electric field at a point with zero electric potential?

Answer: Not necessarily zero. Field and potential are related but independent quantities.

Flashcard 43: Which quantity measures the work done per unit charge by an electric field?

Answer: Electric potential. Potential represents energy per unit charge in electric field.

Flashcard 44: What is the relation between electric field and electric potential?

Answer: $E = -\frac{dV}{dx}$. Field is the negative gradient of potential in one dimension.

Flashcard 45: What is the electric field at a point outside a charged sphere?

Answer: Same as a point charge: $E = \frac{kQ}{r^2}$. Spherical symmetry makes external field identical to point charge.

Flashcard 46: What is the relationship between electric field and force on a charge?

Answer: $F = qE$. Force equals charge multiplied by electric field strength.

Flashcard 47: Identify the electric field at the center of a uniformly charged ring.

Answer: Zero. Symmetry causes all field contributions to cancel at the center.

Flashcard 48: Find the electric field at a point midway between two equal positive charges.

Answer: Zero. Symmetry causes equal and opposite field contributions to cancel.

Flashcard 49: Define an electric dipole.

Answer: Two equal and opposite charges separated by a distance. Basic configuration creating electric dipole moment and field pattern.

Flashcard 50: Find the electric field at a point midway between two equal positive charges.

Answer: Zero. Symmetry causes equal and opposite field contributions to cancel.

Flashcard 51: Which principle explains the behavior of electric fields in superposition?

Answer: Principle of superposition. Vector addition of individual field contributions from multiple sources.

Flashcard 52: Identify the direction of the electric field around a positive point charge.

Answer: Radially outward from the charge. Electric field points away from positive charges in all directions.

Flashcard 53: What is the electric field at a point outside a charged sphere?

Answer: Same as a point charge: $E = \frac{kQ}{r^2}$. Spherical symmetry makes external field identical to point charge.

Flashcard 54: What is the effect of introducing a dielectric in a parallel plate capacitor?

Answer: Reduces the electric field. Dielectric materials decrease field strength by polarization effects.

Flashcard 55: What is the electric field at a point with zero electric potential?

Answer: Not necessarily zero. Field and potential are related but independent quantities.

Flashcard 56: How does the electric field between parallel plates depend on the area of the plates?

Answer: Field is independent of the plate area. Field depends only on charge density and plate separation, not area.

Flashcard 57: What is the formula for the electric field due to a point charge?

Answer: $E = \frac{kQ}{r^2}$. Coulomb's law applied to field strength, where $k$ is the electric constant.

Flashcard 58: State the unit of electric field strength in the SI system.

Answer: Newton per coulomb (N/C). Standard SI unit combining force (N) per unit charge (C).

Flashcard 59: What is the value of the electric constant $k$ in vacuum?

Answer: $k = 8.99 \times 10^9 \text{ N m}^2/\text{C}^2$. Standard value for the proportionality constant in vacuum.

Flashcard 60: Determine the electric field inside a hollow charged spherical conductor.

Answer: Zero. No charges inside hollow conductor means zero internal field.

Flashcard 61: What is the relationship between electric field and force on a charge?

Answer: $F = qE$. Force equals charge multiplied by electric field strength.