Electric Potential and Electric Currents Flashcards

Flashcards covering electric potential, capacitance, energy storage, and electric currents.

Capacitance Calculation

The capacitance of a parallel-plate capacitor with plates of area 0.50 m2 separated by a distance of 2.0 mm is 2.2 x 10-9 F.

Plate Area Calculation

If a parallel-plate capacitor filled with air has a capacitance of 17.3 pF and the plates are separated by 0.050 mm, the plate area is 9.8 x 10-5 m2.

Electric Field Strength

The electric field strength between plates of a parallel-plate capacitor with area 0.20 m2 separated by 1.0 mm when connected to a 6.0-V battery is 6000 N/C.

Electric Field Direction

If the potential difference between the plates of a parallel-plate capacitor with a plate separation of 5.0 cm is 2000 V, the electric field between the plates is 40000 N/C downward.

Additional Charge Flow

When a 6.0-mF air capacitor connected across a 100-V battery is immersed in transformer oil (dielectric constant = 4.5), an additional charge of 2.1 mC flows from the battery.

Stored Energy Calculation (Charge)

The energy stored in a 15 mF capacitor with a charge of 60 mC is 120 mJ.

Stored Energy Calculation (Voltage)

The energy stored in a 15 mF capacitor with 20 V across it is 3.0 mJ.

Work Done Charging Capacitor

The work done in charging a capacitor when 2.00 mC flows onto its plates when connected to a 12.0-V battery is 12.0 mJ.

Voltage Calculation (Energy Stored)

If a 10-mF capacitor stores 2.0 x 10-3 J of energy, the voltage across it is 20 V.

Capacitance Calculation (Area and Separation)

The capacitance of a parallel-plate capacitor with plates of area 1.5 x 10-4 m2 separated by 1.0 mm is 1.3 x 10-12 F.

Charge on Plates Calculation

The charge on the plates of a parallel-plate capacitor with area 1.5 x 10-4 m2 separated by 1.0 mm when connected to a 12-V battery is 1.6 x 10-11 C.

Electric Field Between Plates

The electric field between the plates of a parallel-plate capacitor with area 1.5 x 10-4 m2 separated by 1.0 mm when connected to a 12-V battery is 1.2 x 104 V/m.

Stored Charge Calculation

The charge stored on a parallel-plate capacitor with a plate area of 0.40 m2 and a plate separation of 0.10 mm when charged to a potential difference of 12 V is 0.42 mC.

Stored Energy Calculation

The energy stored in a parallel-plate capacitor with a plate area of 0.40 m2 and a plate separation of 0.10 mm when charged to a potential difference of 12 V is 2.5 mJ.

Capacitance with Dielectric

When a 15-mF capacitor connected to a 50-V battery is fully charged and then a dielectric with a dielectric constant of 5.0 is inserted, the new capacitance is 75 mF.

Voltage with Dielectric

When a 15-mF capacitor connected to a 50-V battery is fully charged and then a dielectric with a dielectric constant of 5.0 is inserted, the voltage across the capacitor's plates becomes 10 V.

Battery

A device that produces electricity by transforming chemical energy into electrical energy.

Car Battery EMF

A car battery has an emf of 12 V consisting of six 2-V cells connected in series.

Current

The total amount of charge that passes through a wire's full cross section at any point per unit of time.

Direction of Convention Current

The direction that positive charges would flow.

Ampere

A coulomb per second.

Amp-hours

Measure of charge.

Resistance of a Wire

(voltage)/(current)

1 W Equivalent

1 J/s

Resistance of a Wire (Proportionality)

Proportional to its length and inversely proportional to its cross-sectional area.

Resistivity of a Wire

The material out of which it is composed.

Lowest Resistivity Material

Silver has the lowest.

Resistivity of Two Copper Wires

Both wires have the same resistivity.

Resistance of Two Copper Wires(Lengths)

The longer wire has twice the resistance of the shorter wire.

Resistance of Two Copper Wires(Area)

The thicker wire has half the resistance of the shorter wire.

Resistance of Two Copper Wires(Length and Area)

Both wires have the same resistance.

Factor of Change

Half as Large

Percentage

300%

Resistivity of Common Metals

Increases as the temperature increases.

Negative Temperature Coefficient

Exist in semiconductors.