Chapter 10 Electrical Circuits Flashcards
What is kirchoff’s second law?
The sum of the potential differences in a circuit is equal to the sum of the electromotive forces in a closed loop
ΣV = Σε
What is a series circuit? What are its properties?
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.
What happens if we have multiple cells in a series circuit?
The EMF’s of each battery are added together to make a total EMF.
What is a parallel circuit? What are its properties?
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.
What is the rule about the potential differences in each branch of a parallel circuit?
The potential differences of all the components on each branch is equal to the EMF
PRACTICE QUESTIONS ABOUT CIRCUITES
DO IT
What is the equation for resistors in series?
Rt = R1 + R2 + R3 + Retc
They are simply added together
What is the equation for resistors in parallel?
1/Rt = 1/R1 + 1/R2 + 1/R3 + 1/Retc
This is because resistors in parallel reduce the resistance
What about the voltage can we determine from resistors in series?
The potential differences from all the resistors can be added together to get the overall potential difference
What are the 4 most important electrical equations?
I = Q / T V = W / Q P = VI V = IR
If a large current is needed, what is the internal resistance that is required?
A low internal resistance
What is internal resistance?
Whenever there is a current in a power source, work has to be done to move the charges so there is an internal resistance
What is lost volts?
It is the volts that have been lost to the internal resistance of a battery
What is the difference between the terminal pd and the emf?
The terminal pd is the potential difference across the battery.
Terminal Pd = EMF - Lost volts
What is the equation for EMF?
EMF = Terminal pd + Lost volts