Circutis

Question 1

Current

Answer 1

Movement of positive charge through a conductive material over time and is given is Amperes (C/S)

Question 2

Voltage

Answer 2

Potential difference between two points and is given in volts (J/C)

Question 3

Electromotive force (emf)

Answer 3

Potential difference of the voltage source for a circuit, usually a battery and is given in volts

Question 4

Conductivity

Answer 4

The reciprocal of resistance and is a measure of permissiveness to current flow, measured in siemens (S)

Question 5

Ohm’s Law

Answer 5

For a given resistance, the magnitude of the current through a resistor is proportional to the voltage drop across the resistors

Question 6

Kirchhoff’s Current Law

Answer 6

Kirchhoff’s Current Law says that the sum of all currents flowing into a node equals the sum of currents flowing out of the node.

Question 7

Kirchhoff’s Voltage Law

Answer 7

The sum of voltages around a loop is zero.

• You can trace a loop starting from any node. Walk around the loop and end up back at the starting node, the sum of voltages around the loop adds up to zero.
• You can go around the loop in either direction, clockwise or counterclockwise. Kirchhoff’s Voltage Law still holds.
• If a circuit has multiple loops, Kirchhoff’s Voltage Law is true for every loop.

Question 8

How does adding or removing a resistor change the total resistance of a circuit with resistors in series? In parallel?

Answer 8

Adding a resistor in series increases the total resistance of a circuit; removing one in series decreases the total resistance in the circuit
Adding a resistor decreases resistance in parallel, while removing one increases it.

Question 9

What four physical quantities determine the resistance of a resistor?

Answer 9

Resistivity, length, cross sectional area, and temperature

Question 10

How does power relate to current, voltage and resistance

Answer 10

P= IV= I^2R= (V^2/R)

Question 11

What does internal resistance of a battery do?

Answer 11

It lowers the available voltage for the circuit and thus lower the current for any given resistance.

Question 12

What happens when you put a non-conducting material (dielectric material) between the two plates?

Answer 12

Capacitance increases

Question 13

How does a dielectric in isolated capacitors Increase the capacitance?

Answer 13

Reduce the voltage

Question 14

Capacitance equation

Answer 14

C= Q/V

Question 15

Units for capacitance

Answer 15

Farad (1F= 1C/V)

Question 16

Uniform electric field between plates equation

Answer 16

E=V/d

Question 17

Potential energy stored in capacitance

Answer 17

U= 1/2CV^2 or qV/2

Question 18

Capacitance due to dielectric material

Answer 18

C(new)= kC

Question 19

How does the capacitance increase in a dielectrics in circuit capacitors?

Answer 19

By increasing the amount of charge by a factor of dielectric constant and voltage constant because battery is there so wants to maintain a constant voltage.

Question 20

Capacitors in a series

Answer 20

Total capacitance decreases
1/Cs= (1/C1 + 1/C2 + 1/C3…)
Charge same on each capacitor
Voltage is sum of individual capacitors

Question 21

Capacitors in parallel

Answer 21

Total capacitance increases
Cp= C1 +C2 +C3 +Cn....
Voltage same across each capacitor
Same voltage at each capacitor as the battery 
Greater capacitance= greater charge

Question 22

How does a dielectric affect capacitance, voltage and charge

Answer 22

A dielectric will increase capacitance. If the capacitor is isolated, its voltage will decrease when a dielectric is introduced
If its in a circuit, its voltage is constant because it is dictated by its voltage source.
If the capacitor is isolated, the stored charge will remain constant and if its in a circuit the stored charge will increase.

Question 23

How does adding or removing a capacitor in series and parallel affect capacitance?

Answer 23

Adding a capacitor in a series decreases the total capacitance of a circuit; removing one in a series increases the total capacitance in the circuit
In parallel, adding a capacitor increases capacitance and removing it decreases it.

Question 24

What physical qualities contribute to the capacitance of a capacitor?

Answer 24

Surface area, distance, and dielectric constant all contribute to the capacitance of a capacitor.

Question 25

Ammeter

Answer 25

Measures:Current
Placement: In series
Ideal resistance: 0
Need circuit to be on

Question 26

Voltmeter

Answer 26

Measures: Voltage
Placement: Parallel
Ideal resistance: Infinite
Need circuit to be on

Question 27

Ohmmeter

Answer 27

Measures:Resistance
Placement: Two points in series with circuit
Ideal resistance: 0
Does NOT Need circuit to be on

Question 28

Resistors generate

Answer 28

Power