Electricty Flashcards
What is the ability of a variable resistor? + 1 use - Electricity
A resistor which can alter its resistance
Used in light switch dimmers
What is the ability of a thermistor? + 1 use - Electricity
A resistor which depends on temperature. As temperature increases, resistance decreases
Can be used in heat activated fire alarms and thermostats
What is the ability of a diode? - Electricity
A diode only allows current to flow in one direction
What is the ability of an LDR? + 1 use - Electricity
As light intensity increases the resistance decreases. Can be used in automatic lights that turn on when dark
What is the difference between AC and DC? - Electricity
In AC, the flow of electrons constantly changes direction, whereas in DC the flow of electrons stays the same direction
What is the equation linking charge, current and time? - Electricity
Charge (Q) = Current (I) x Time (t)
What electrical component measures current? + should an ammeter be in series or parallel to measure a component? - Electricity
Ammeter, should be placed in series
What component measures voltage and how is it connected? - Electricity
A voltmeter, which is always connected across a component
What equation links voltage, energy and charge? - Electricity
Voltage (V) = Energy (J) / Charge (Q)
What equation links voltage, current and resistance? - Electricity
Voltage (V) = Current (I) x Resistance (Ohms)
What happens if a component is broken in a SERIES circuit? - Electricity
The whole circuit will cease to function
What is the rule concerning current in a SERIES circuit? - Electricity
The current is the same around the entirety of the circuit (I1 = I2 = I3)
What is the rule concerning voltage in a SERIES circuit? - Electricity
The voltage across components throughout the circuit will all add to the value of the voltage across the cell
(V1 + V2 = V (cell))
What is the rule concerning resistors in a SERIES circuit? - Electricity
As current must flow through all parts of the circuit, the resistance of all total resistors is added to find the total resistance (total R = R1 +R2)
What is the rule concerning current in a PARALLEL circuit? - Electricity
The current will split among the different pathways, indicated by ammeters in different areas of the circuit
What is the rule concerning voltage in a PARALLEL circuit? - Electricity
The voltage in a parallel circuit splits evenly between pathways, as the energy transferred by electrons is the same in any path
What is the rule concerning resistance in a PARALLEL circuit? - Electricity
Resistance is reduced as electrons split between paths, and therefore do not have to go through 1 resistor
How do wires in a circuit heat up? - Electricity
Electrons collide with the metal ions, causing more vibrations from the ions, meaning that the wire temp increases
What is the equation linking power, current and potential difference? - Electricity
Power (W) = Current (I) x Voltage (V)
What equation links power, current and resistance? (HINT - ^2) - Electricity
Power (W) = Current^2 (I) x Resistance (Ohms)
What can affect charged objects through contact with other charged objects? - Electricity
Static electricity
How can objects become electrically charged through friction? + what charge do these objects that gain electrons have? - STATIC Electricity
Electrons can be transferred by friction between objects, with the object gaining electrons becoming negatively charged
What happens to mean the electrons can transfer from one object to another? - STATIC Electricity
By applying friction, the electrons gain energy, enough to leave their atom
Why can a balloon stick to a wall? - STATIC Electricity
The balloon has gained electrons to become negatively charged and is attracted to the positively charged wall
