Term
in order to have an electrical potential difference (aka voltage) that drives current in an electric circuit, we need a battery or an electric generator ,in this case the battery is a source of ______ 

Definition
electromotive force( emf)
(note this is not really a force measured in Newtons, just a bad name). 


Term
describe the electromotive force( emf) of a batery or a electric generator
(aka a source that can generate electrical energy) 

Definition
the potential difference btwn the terminals of the source, where no current flows to an external circuit.
unit: volts 


Term
true or false :is a battery a source of constant current?
if false make it true 

Definition
false, the current out of a battery varies according to the resistance in the circuit. 


Term
true or false :is a battery a source of constant voltage?
if false make it true 

Definition
sort of;
a battery is a source of constant voltage, but NOT perfectly constant
battery has a small internal resistance, which reduces the actual voltage from the ideal emf.



Term
terminal voltage def (words) 

Definition
the voltage gained by the battery with respect to terminals in the battery ( ex A & B)
has to equal the sum of all the voltage drops due to the prescense of resistors in the circuit 


Term
when no current is drawn from the battery terminal voltage equals? 

Definition
the emf (which is determined by the chemical rxns in the battery) 


Term
when a current, I, flows naturally from the battery the terminal voltage equals? 

Definition
there is an internal drop in voltage equal to Ir
I= current
r= internal resistance
(aka this is theACTUAL terminal voltage) 


Term
when 2 or more resistors are connected end to end along a single path from the battery , they are said to be connected in _____. 

Definition


Term
when 2 or more resistors are connected end to end in a series
1.the total voltage is equal to?
2.the total (equivalent)resistance is equal to ? 

Definition
1. sum of the voltages across each resistor
(V _{total}= V1+V2+V3)
=
recall ohm's law V=IR
=
IR1+IR2+IR3
2.Req= R1 +R2+ R3 


Term
for Resistors in Series:
The current through each resistor is ______ (equal, less, more), while the voltage depends on the _______.
The sum of the voltage 'drops'across the resistors as you go across the all the resistors in the circuit euqals the _____.


Definition
1.the same
2. resistance
3. battery voltage



Term
for Resistors in Series:
what occurs when you add more resistance to thre circuit? 

Definition
the current through the circuit will decrease.



Term
1.what is the current of a 12 V battery if it is connected to a 4Ω resitor?
2.also calc for 3 4Ω resitors in a series? 

Definition
1. V= IR
I= V/R
I=12/4Ω
I= 3A
2. Find total R:
3 x 4Ω = 12Ω
I= 12/12Ω
I = 1 A



Term
for a series of resistors that have parallel connection
what happens the current?
what happens to the voltage across each resistor 

Definition
1.the current is split into seperate paths
2.the voltage across each resistor is the same 


Term
explain the difference btwn resistors that are connected
parallel vs series 

Definition
Parallel: how a house, buliding is wired
, if you disconnect one device the other devices are not interupted.
Series: if one device is disconnected, current is stopped to the others. 


Term
For a parallel arrangemnet of resisitors, why is the voltage across each resistor is the same? 

Definition
the full voltage of the battery is applied to each resistor. 


Term
example: what is the equivalent resistance of 2 4Ω 'resistors' connected in parallel? 

Definition
1/R_{eq =} 1/4Ω + 1/4Ω
= 2/ 4Ω
= 1/2Ω
so Req= 2
(u flipped 1/2 to 2/1) 


Term
why is the net resistance less for resistors connected parallel? 

Definition
for resistors connected in a parallel circuit the net resistance is less than the resitance than a SINGLE resistor
b/c the parallel arrangemnt allows the current additional paths to follow. 


Term
when are Kirchhoff’s Rules applied? 

Definition
whenSome circuits
cannot be broken down into series & parallel connections 


Term
Kirchhoff’s Rules: what is the junction rule? 

Definition
The sum of currents entering a junction
=
the sum of the currents leaving it. 


Term
Kirchhoff’s Rules:
what is the loop rule? 

Definition
The sum of the changes in potential around a closed loop ( aka a closed circuit) is zero 


Term
when 2 or more sources of emf such as batteries are arranged in a series, how is the total voltage calculated? 

Definition
the total voltage is the alegebraic sum of the voltages. 


Term
EMFS in parallel only are useful only if 

Definition
only if the voltages of the emfs are the same. 


Term
T or F: EMFs in a parallel arrangement is used to increase voltage
whether true or false , explain 

Definition
False, a parallel arrangement are used to SAVE energy when large currents are needed.
↓
(how they save energy)each of the cells in parallel produce only a fraction of the current.
↓
so the energy loss due to internal resistance would less LESS compared to a single EMF.
(battery will go dead less quickly) 


Term
Circuits Containing Capacitors in Parallel have ______ (same, greater, less)voltage across each one of the capacitors. 

Definition


Term
For Circuits Containing Capacitors in Parallel
what is the formula for the total capacitance? (ex you have 3 capacitors) 

Definition
Q= C eq V= C_{1 }V+ C_{2 }V+C_{3 }V
(recall voltages are equal for all the capacitors)
or
C eq = C_{1 }+ C_{2 }+C_{3 }
* recall Q= CV
Q=charge
C=capacitance
V= voltage
so its saying the total capitance it just the sum of the capitances
(not plugging into the formula which is V=Q/C). 


Term
Why is it useful to connect capacitors in parallel? & why? 

Definition
is to increase the capitance
b/c we are increasing the area of the plates where charge can accumulate 


Term
Circuits Containing Capacitors in Series have ________(same,greater,less) charge. 

Definition


Term
Give the formula the total (equivalent) capitance of a circuit with 3 capacitors. 

Definition
recall Q=CV
V=Q/C1+ Q/C2+ Q/C3
=
Q( 1/C1 + 1/C2+ 1/C3)
1/Ceq= 1/C1 + 1/C2 + 1/C3
just flip it b/c this is the reciporcal
(e.g 1/2 = 2/1=2) 


Term
do rc circuits flash cards next 

Definition
do rc circuit flash card next 


Term

Definition
current (remember unit is amps) 


Term

Definition


Term
Ammeters and Voltmeters are based on _________, unless they are digital 

Definition


Term
b/c the current in a circuit passes through the ammeter; the ammeter should have _____(high/low) resistance so as not to affect the current. 

Definition


Term
A voltmeter should not affect the voltage across the circuit element it is measuring; therefore its resistance should be very (small/large) 

Definition


Term
An ohmmeter measures resistance; it requires ______ 

Definition
1.resistance
2.a battery to provide a current
*If the meter has too much or (in this case) too little resistance, it can affect the measurement.



Term
Convential current is flow of current from the _____ terminal to the ___ terminal 

Definition


Term
the resistance of a conductor is a measure of it's 

Definition
resistance to current flow. 


Term

Definition
a device that is used intenially to cause a voltage drop in the circuit 


Term

Definition

