Unit 2 - Electricity Flashcards
Electrons move from..?
the negative terminal of a battery to the positive terminal.
Electrons have a what charge?
Negative
Protons have a what charge?
Positive
Neutrons have a what charge?
Neutral
What is the equation for Charge?
Charge = Current x Time
Q = I x t
Time is measured in..?
Seconds
Charge is measured in..?
Coulombs
Current is measured in..?
Amps
Voltage/Potential Difference is measured in..?
Volts
Resistance is measured in..?
Ohms
Current is..
the rate of flow of charge.
Charge is..
Charge is the amount of electricity travelling through a circuit.
Energy (in a circuit) is..
the work done by the source of electricity to maintain the rate of flow of charge in a circuit.
Voltage/ Potential Difference is..?
The difference in potential between two points of a circuit. Causes a current to flow.
Resistance is..?
the force slowing down the current.
1V = ?
1J/C
Voltage (Potential Difference) Symbols and Units
Quantity Symbol - V
Unit = Volt
Symbol for Unit - V
Energy Transferred (Work Done) Symbols and Units
Quantity Symbol - E
Unit - Joule
Symbol for Unit - J
Charge Symbols and Units
Quantity Symbol - Q
Unit - Coulomb
Symbol for Unit - C
What is the equation for Energy Transferred?
Energy Transferred = Charge x Voltage
E = Q x V
Energy Transferred = Current x Voltage x Time
E = I x V x t
What is the equation for Power?
Power = Current x Voltage
P = I x V
The higher the Potential Difference of the source..?
the greater the push, therefore the current increases.
Any electrical component with resistance causes?
The current in the circuit to decrease
Electrical energy to be transferred away from the charge (it is lost as thermal energy)
What is Ohms Law in words?
Ohms Law states electric current is proportional to voltage and inversely proportional to resistance.
What is the equation of Voltage?
Voltage = Current x Resistance - Ohms Law
V(V) = I(A) x R(Ω)
What happens to the resistance in a Light Dependant Resistor (LDR)?
The resistance of a LDR is large when it’s dark but as the light intensity increased the resistance decreases.
What happens to the resistance in a Thermistor?
As the temperature increases, the resistance in a thermistor decreases.
What is a Variable Resistor?
Can be used in an electrical circuit to control the size of the current
Helps vary to current easily
The resistance can be steadily altered by turning a dial or moving the slider
What happens in Filament Lamps Graphs
The resistance of the filament increases as the temperature increases. The IV graph isn’t directly proportional.
What happens in a Filament Lamp - A type of lightbulb
The filament is a piece of wire with really high resistance because it’s so thin. Current passes through high resistance filament, the electrons collide with ions in the wire causing them to vibrate. These vibrations raise the temperature so much it glows.
Diode
A diode is a component with high resistance in one direction only. Since there is high resistance in one direction, current can only flow in the other direction.
LED - Light Emitting Diode
It produces light when a current flows through it in the forwards direction. LEDs are often used for tvs and computers because they use a smaller current than other types of lighting.
How can LEDs and lamps be used in a circuit?
They can be used to indicate the present of current in a circuit.
How does the current in a series circuit depend on the applied voltage and the number and nature of other components?
As voltage increases the current also increases. In general, the more components in a circuit, the lower the current.
What if you increase the resistance using resistors, metal filament lamps & diodes what happens to the current in the circuit?
How do you investigate this?
The current decreases and voltage increases.
Using an ammeter & measuring the current w/ & without resistors, metal filament lamps & diodes or w/ different voltage levels measured (voltmeter)
How can you increase the resistance in a circuit?
By using resistors, metal filament lamps & diodes.
What are Ohmic Resistors and what are some examples?
Resistors that obey Ohm’s Law. Any increase in voltage creates a linear increase in the current.
example: resistors (variable resistors)
What are Non-ohmic Resistors and what are some examples?
Resistors that do not obey Ohm’s Law. Any increase in voltage creates a non-linear increase in the current. The resistance of the material changes based on the current moving through it.
example: filament bulbs, diodes, etc.
In a parallel circuit the electrons (current)..?
gets split between the different paths.
In a series circuit, the electrons (current)..?
move through each and every component (the same in all points of the circuit)
What is a Series Circuit?
The current has only one path.
What is a Parallel Circuit?
The current has more than one path.
Advantages of Parallel
If one light bulb breaks, all other light bulbs remain on. Light bulbs in a parallel are brighter than the light bulbs in a series, because the potential difference remains the same amongst all circuits.
Series circuits are used when..?
Series circuits are useful when you need to add more voltage to increase power, when you need a simpler wiring configuration, or when you need to quickly tell if a component in the circuit is not working.
Parallel circuits are used when..?
Parallel circuits keep the lights on in our homes and ensure that different appliances continue to work, even if other appliances are turned off. Parallel circuits are the standard circuits found in home electrical wiring.
Electric current in solid metallic conductors is..?
A flow of negatively charged electrons
Why is current conserved at a junction in a circuit?
The current is shared between each component connected in parallel. The total amount of current flowing into the junction, or split, is equal to the total current flowing out. The current is described as being conserved.
In a series circuit voltage is..?
spilt between components.
In a parallel circuit voltage is..?
the same at all points in the circuit (the same across all points in a circuit).
