Flashcards in Theory Deck (57)
What is ohm's law?
Current is directly proportional to the voltage and inversely proportional to the resistance of the circuit.
E= I x R. I = E/R. R=E/I
What are the Advantages of a 3 wire Edison system?
2 different voltages
Uses Less conductor material
Less line loss
Using ohm's law, how would you find E?
E = I x R
In a series circuit, the current ( I ) is directly proportional to the resistance of the circuit.
True or False?
False....... The current ( I ) is inversely proportional to the resistance of the circuit.
What is coloumb?
A coulomb represents a quantity of charge provided by a massive number of electrons. Approximately
6.28 x 10>18 of them.
What is the unit of measurement for charge? What is it's symbol
Coulomb's..... The unit symbol is C
Describe the equation:
I = Q/T
Current = Quantity of charge / unit of time.
What is kirchoff's current law as it applies to a parallel circuit?
All current values entering a junction point must equal all currents leaving the junction point.
What is another name for a parallel circuit?
A branch circuit
Lights and receptacles are almost always connected to what type of circuit?
A branch circuit ( parallel circuit )
Describe a parallel circuit.
A circuit with more than one path.
The total resistance of a parallel circuit is always less than he resistance of the smallest branch.
True or False
The flow of electrons between two points from negative to positive.
What is resistance?
The opposition to flow.
What is charge?
A build up of electrons.
What is voltage?
A potential difference in charge.
What are the three basic properties of an electric circuit?
Current, voltage ( emf ), resistance.
What is the name of the force that maintains a voltage?
When a fifth resistor is added in parallel to four parallel connected resistors, what happens to the total current?
The current increases
When a fifth resistor is added in parallel to four parallel connected resistors, what happens to the total resistance ?
The Resistance decreases.
In a series circuit, the voltage drop is directly proportional to the resistance rating.
True or False
List six methods for producing emf.
Pressure/Piezo Electric Effect
Light/Solar ( photo voltaic cells)
Heat (furnace, thermocouples)
Describe the basic structure of an atom.
A nucleus containing protons and electrons.
Name the two main particles in the venter of an atom.
Protons and neutrons.
What makes up the nucleus of an atom?
Protons ( + ) and neutrons ( -/+ )
Name the particles that rotate in orbit of the atom.
Electrons ( - )
Materials with a low resistance are known as......
Materials with a high resistance are known as.......
What is kirchoff's voltage law as it applies to series circuits?
The sum of the voltage drops must equal the total applied voltage.
E = V1 + V2 + V3.......
E - V1 - V2 - V3 = 0