Electricity and Magnetism flashcards

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What is electric charge?Charge and Electric Forces: A property of matter associated with electric interactions.
What charge does an electron have?Charge and Electric Forces: Negative.
What does electrically neutral mean?Charge and Electric Forces: Net positive and negative charges balance.
What is charge conservation?Charge and Electric Forces: Total charge remains constant in an isolated system.
What is Coulomb’s law magnitude?Charge and Electric Forces: F = k|q₁q₂|/r² for point charges.
What does r represent?Charge and Electric Forces: Distance between modeled charges.
What happens when r doubles?Charge and Electric Forces: Force becomes one quarter in the point-charge model.
Can a neutral object be attracted?Charge and Electric Forces: Yes, polarization can induce attraction.
What is electric field E?Charge and Electric Forces: Electric force per positive test charge.
What direction defines E?Charge and Electric Forces: Force direction on a positive test charge.
What is voltage?Charge and Electric Forces: Electric potential difference, energy per charge.
What is one volt?Charge and Electric Forces: One joule per coulomb.
What is current?Current, Voltage, and Resistance: Charge flow rate I = ΔQ/Δt.
What is one ampere?Current, Voltage, and Resistance: One coulomb per second.
What is conventional current direction?Current, Voltage, and Resistance: Direction a positive charge would move.
Are charges used up in a steady simple circuit?Current, Voltage, and Resistance: No; energy is transferred while charge is conserved.
What is potential difference?Current, Voltage, and Resistance: Energy change per charge between two points.
What is the voltage equation?Current, Voltage, and Resistance: ΔV = ΔE/q.
How is voltage measured in a circuit?Current, Voltage, and Resistance: Across two selected points.
What does a load do?Current, Voltage, and Resistance: Transfers electrical energy into other forms.
What is resistance?Current, Voltage, and Resistance: The ratio of voltage across a component to current through it.
What is Ohm’s law for an ohmic resistor?Current, Voltage, and Resistance: V = IR.
What is the ohm?Current, Voltage, and Resistance: One volt per ampere.
Are all devices ohmic?Current, Voltage, and Resistance: No, some have nonlinear voltage–current behavior.
What is a series circuit?Series and Parallel Circuits: Components connected along one current path.
What is series equivalent resistance?Series and Parallel Circuits: The sum of individual resistances.
How is series current related?Series and Parallel Circuits: The same current passes each component.
What happens if the only series path opens?Series and Parallel Circuits: Current stops in the entire path.
What is a parallel circuit?Series and Parallel Circuits: Multiple branches sharing the same two nodes.
What is branch voltage in parallel?Series and Parallel Circuits: The same across each branch in the ideal model.
What is the junction current rule?Series and Parallel Circuits: Incoming current equals total outgoing current.
What happens to ideal R_eq when a branch is added?Series and Parallel Circuits: It decreases if the added path conducts.
What is electrical power?Series and Parallel Circuits: P = IV for a specified component under convention.
What is resistive power?Series and Parallel Circuits: P = I²R or V²/R for an ohmic resistor.
What is energy over constant power?Series and Parallel Circuits: E = Pt.
What is a short circuit?Series and Parallel Circuits: An unintended very low-resistance path that can draw excessive current.
What is a magnetic field?Magnetic Fields and Electromagnets: A vector field influencing magnets and moving charges.
What is a compass used for here?Magnetic Fields and Electromagnets: Indicating local magnetic-field direction.
How do like magnetic poles interact?Magnetic Fields and Electromagnets: They repel.
Do cut bar magnets isolate a single pole?Magnetic Fields and Electromagnets: No, each piece usually has both poles.
What surrounds a current-carrying wire?Magnetic Fields and Electromagnets: A magnetic field circling the wire.
What is a solenoid?Magnetic Fields and Electromagnets: A coil of wire that produces a magnetic field when current flows.
What happens when coil current reverses?Magnetic Fields and Electromagnets: The field direction reverses.
Does a current-made field require a permanent magnet?Magnetic Fields and Electromagnets: No.
What is an electromagnet?Magnetic Fields and Electromagnets: A magnetically active current-carrying device, often a coil.
What can strengthen a coil field?Magnetic Fields and Electromagnets: More current or suitable turns and core, within limits.
What is a relay?Magnetic Fields and Electromagnets: An electrically controlled switch using an actuator such as an electromagnet.
Can an electromagnet warm?Magnetic Fields and Electromagnets: Yes, resistive heating can occur.
What does an electric motor convert?Motors, Generators, and Induction: Electrical energy to mechanical output and other transfers.
What produces motor torque?Motors, Generators, and Induction: Magnetic forces on current-carrying conductors.
Does a motor need energy input?Motors, Generators, and Induction: Yes.
Can motor losses warm it?Motors, Generators, and Induction: Yes.
What is electromagnetic induction?Motors, Generators, and Induction: Induced emf from changing magnetic flux through a circuit.
What is magnetic flux here?Motors, Generators, and Induction: A measure of magnetic field through a chosen surface.
When can induced current flow?Motors, Generators, and Induction: When induced emf acts around a closed conducting path.
What does Lenz’s law specify?Motors, Generators, and Induction: The induced effect opposes the change in flux.
What does a generator convert?Motors, Generators, and Induction: Mechanical energy into electrical energy.
What does a transformer change?Motors, Generators, and Induction: Alternating voltage through coupled magnetic flux.
What is an ideal turns ratio?Motors, Generators, and Induction: V_s/V_p = N_s/N_p.
Does a standard transformer work on steady DC?Motors, Generators, and Induction: Not continuously after its switching transient.