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AP Physics 1 > Electric Circuits > Flashcards

Flashcards in Electric Circuits Deck (47):
1

What is the equation for electric current?

I=Δq/Δt
Units: C/s or A (Amps)

2

What is an Electric Current?

Moving electric charges; measures the amount of charge passing a given point every second

3

What does a battery do in a circuit?

It supplies the potential difference (voltage) needed to maintain a continuous flow of charge

4

What path does an electric charge take in a circuit?

Positive to negative

5

What is a Resistor?

Device whose function is to oppose the current of a circuit

6

What is an Ammeter?

Device that measures the current; used in series with a circuit

7

What is a Voltmeter?

Device that measures potential difference; used in parallel to a circuit

8

Is there an observable difference in readings of an ammeter when it is moved to a different location?

No

9

Is there an observable difference in readings of an voltmeter when it is moved to a different location?

No

10

What differences in readings of a ammeter/voltmeter are observable?

Difference in emf across the terminals of a battery

11

What is Electromotive Force (emf)?

Potential difference; voltage
Units: Volts

12

What is a Circuit?

A complete loop/circle of wire that allows for continuous flow of charge

13

What is Terminal emf?

First emf reflects the work done by the battery to move more change through the circuit and across terminals of the battery; total voltage; also known as internal emf

14

What is Resistance?

Electrical friction caused by the interaction of flowing electrons and molecules of a wire

15

What is resistance dependent on?

Temperature

16

What does an increase in temperature do to the resistance of a circuit?

Increases the current flow

17

What is Ohm's Law?

If temperature is constant, as the voltage increases, a greater flow of current will be observed; direct relationship between voltage and current

18

What is the equation for resistance? (aka Ohm's Law)

R=V/I or V=IR
Units: ohms (Ω)

19

What is the slope of a voltage vs current graph represent?

slope=resistance
R=V/I

20

What is Resistivity?

Measure of resisting power of a certain material to the flow of an electric current (ρ)

21

What is the equation for resistivity?

R=ρL/A
L=length of wire
A=area of cross section
Units (ρ)=Ω*m

22

What happens if a wire has a smaller cross section area? (R=ρL/A)

The resistance of the wire will increase

23

What happens if the length of the wire increases? (R=ρL/A)

The resistance of the wire will increase

24

What is the equation for the total power of a circuit?

P=ΔVI
Units: Watts (W)

25

What is equation for electrical energy?

E=Pt or E=WIt or E=I^2Rt
Units: Joules (J)

26

What is a Series Circuit?

A circuit consisting of two or more resistors sequentially placed within one circuit

27

What will happen if there is a break (ie. light bulb goes out) in a series circuit?

The entire circuit will shut down; the continuous path is broken

28

Is the current of a series circuit the same or different throughout the circuit?

The current is the same because there is only one circuit

29

Is the terminal emf (or voltage) of a series circuit the same or different throughout the circuit?

The voltage is different; it is equal to the sum of all the emf's across all of the resistors

30

Where is there potential drop in a circuit?

Across each resistor

31

What is Potential Drop?

The amount of voltage loss that occurs through all or part of a circuit due to resistance; also known as voltage drop

32

What will happen to a series circuit if more resistors are added?

The electric current will decrease by increasing the resistance of the current, if the voltage is the same; as resistance increases, current decreases

33

What is the equation for the current of a series circuit?

I(total)=I1=I2=I3
Current is the same throughout

34

What is the equation for the voltage of a series circuit?

V(total)=V1+V2+V3
IR(total)=IR1+IR2+IR3
Voltage is different/shared

35

What is the equation for the resistance of a series circuit?

R(total)=R1+R2+R3

36

What is a Parallel Circuit?

A circuit consisting of two or more resistors connected across each other to a common point of potential difference

37

What happens if there is a break (ie. light bulb going out) in a parallel circuit?

The circuit does not go out because the current can flow to through the other path

38

Is the voltage of a parallel circuit the same or different throughout the circuit?

Same because each resistor is connected at a common potential point; voltage across each resistor is equal to the source voltage

39

What will happen in a parallel circuit if more resistors are added?

Will increase the effective circuit current by decreasing the circuit resistance; as resistance decreases, current increases

40

What is the equation for the voltage of a parallel circuit?

V(total)=V1=V2=V3
Voltage is the same throughout

41

What is the equation for the current of a parallel circuit?

I(total)=I1+I2+I3
V/R(total)=V/R1+V/R2+V/R3
Current is different/shared

42

What is the equation for the resistance of a parallel circuit?

1/R(total)=1/R1+1/R2+1/R3

43

What are Kirchhoff's Circuit Laws (2)?

Junction Rule (current) and Loop Rule (voltage)

44

What is the Junction Rule?

The sum of currents flowing into a branch must equal the sum of currents leaving

45

What is the Loop Rule?

The sum of all emfs around a loop is equal to the sum of the potential drops around the loop

46

Where should an ammeter be placed in a circuit?

In series, right before or after the given resistor; an ammeter measures the current

47

Where should a voltmeter be placed in a circuit?

In parallel, across the given resistor; a voltmeter measures the voltage