Chapter 10 Electrical Circuits Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is kirchoff’s second law?

A

The sum of the potential differences in a circuit is equal to the sum of the electromotive forces in a closed loop
ΣV = Σε

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a series circuit? What are its properties?

A

It is a circuit with only one path for the current to flow.
The currents are the same in every position
The emf is shared between all the components in the series circuit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens if we have multiple cells in a series circuit?

A

The EMF’s of each battery are added together to make a total EMF.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a parallel circuit? What are its properties?

A

It is a circuit that allows more than one path for the current to travel. The amount of current is dependent on the resistance of each path, more resistance, more current.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the rule about the potential differences in each branch of a parallel circuit?

A

The potential differences of all the components on each branch is equal to the EMF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

PRACTICE QUESTIONS ABOUT CIRCUITES

A

DO IT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the equation for resistors in series?

A

Rt = R1 + R2 + R3 + Retc

They are simply added together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the equation for resistors in parallel?

A

1/Rt = 1/R1 + 1/R2 + 1/R3 + 1/Retc

This is because resistors in parallel reduce the resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What about the voltage can we determine from resistors in series?

A

The potential differences from all the resistors can be added together to get the overall potential difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 4 most important electrical equations?

A
I = Q / T
V = W / Q
P = VI
V = IR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

If a large current is needed, what is the internal resistance that is required?

A

A low internal resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is internal resistance?

A

Whenever there is a current in a power source, work has to be done to move the charges so there is an internal resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is lost volts?

A

It is the volts that have been lost to the internal resistance of a battery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the difference between the terminal pd and the emf?

A

The terminal pd is the potential difference across the battery.
Terminal Pd = EMF - Lost volts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the equation for EMF?

A

EMF = Terminal pd + Lost volts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the equation for lost volts?

A
Lost volts = Ir
EMF = V + Lost volts
EMF = V + Ir
EMF = I(R+r) 
Where I is the current, R is the resistance of the circuit and r is the internal resistance
17
Q

What can be obtained from a graph of voltage against current of a battery?

A

The y axis (voltage axis) intercept is the EMF of the battery.
The Gradient is the internal resistance

18
Q

What is the benefit of having a low internal resistance?

A

It allows batteries to charge and discharge quicker with more current because they don’t heat up as much.

19
Q

What is a potential divider?

A

It divides up the voltage so that any value of voltage can be acquired up to the voltage of the supplied power source

20
Q

What does the circuit for a potential divider look like?

A
12v -----
           [] R1
            |-------- Vout
           [] R2
0v --------------
21
Q

What are the two equations for potential divider circuits?

A

V1 / V2 = R1 / R2
and
Vout = (R2 / (R1 + R2)) x Vin

22
Q

What is a use of potential divider circuits and how can this be implemented?

A

They can be used in sensing circuits by replacing one of the resistors with a sensing variable resistor like an LDR or a thermistor

23
Q

What is a potentiometer?

A

It is a circuit component that changes the value of V out from 0 to Vmax. It works by varying both R1 and R2 at the same time.

24
Q

What is the benefit of a potential divider circuit vs a variable resistor

A

A variable resistor can only vary the voltage a limited amount where as a potential divider circuit has a larger range that it can vary.