Electricity
Universal
Electricity flows based on differences in...
electric potential
What is a series circuit?
A circuit that only has one path from one end of the battery to the other.
What is a parallel circuit?
A circuit with multiple paths from one end of the battery to the other.
Describe the mechanism by which an incandescent lightbulb produces light.
The electric current travels through a metal filament in the light, causing it to heat up, get excited, and produce visible light.
What causes electrical charge?
An imbalance in subatomic particles (protons vs electrons)
Are electric fields vector or scalar? What does this mean?
Electric fields are vector, which means that at any location in an electric field, the charge has both magnitude (size) and direction.
How does the light bulb brightness of 3 light bulbs compare on a series circuit vs parallel circuit?
The light bulbs on the series circuit will get more dim the further they are from the battery, while the bulbs on the parallel circuit will all be the same brightness.
Using a battery, 2 alligator clip wires, and a lightbulb, what conditions need to be met for a lightbulb to light up? In what direction will the electric current flow?
The alligator clip wires need to each be connected to one end of the battery, and the light bulb, allowing an electric current to flow from the positive end of the battery, through the light bulb, and into the negative end of the battery.
LED stands for ‘light-emitting diode.’ What does this mean?
This means that it is a diode, or an appliance that only allows electricity to flow in one direction through it, and that it emits light when electrically charged.
Why are some objects more likely to ‘give up’ electrons and others more likely to receive electrons?
It depends on how many empty spaces the object's atoms have in their outermost electron shell. Atoms with very few electrons are more likely to give them up, while atoms with many are likely to receive them.
Describe the conditions under which the flaps of an electroscope would stick out, and why. Be sure to reference the distribution of subatomic particles (protons, electrons, etc.)
The flaps of an electroscope would stick out if both had the same charge, either positive or negative, as like charges repel. This means that either could be full of electrons (negative), or not have any (positive).
How will the brightness of a light bulb change if I add a resistor to the circuit after the light bulb?
The brightness of the light bulb will not change because the resistor is not limiting the electric current until after it passes through the light bulb.
What is the relationship/equation between the voltage, current, and resistance in a circuit, as detailed by Ohm’s Law?
Voltage = Current x Resistance
Current = Voltage / Resistance
Resistance = Voltage / Current
How do fluorescent light bulbs work?
An electric current is sent through a gas, exciting the gas atoms, causing them to emit light.
What happens to a negative balloon when you bring it close to a neutral wall, and why? Be specific!
The electrons in the balloon repel the electrons in the wall, creating a locally-positive zone in the wall that the balloon is attracted to, causing it to stick.
According to Coulomb’s Law, how would the force two positively-charged objects exert on each other change as they are brought closer together?
The force would increase, as Coulomb's Law states that the force that two electrically charged objects exert on each other is proportional to their charge, and inversely proportional to their distance from each other.
Why are resistors useful components in electrical circuits?
They ensure that some electrical components aren't given too much voltage/current
Which type of circuit, series or parallel, will drain a battery faster, and why?
The parallel circuit, because each of the individual circuits will draw from the battery.
Why are diodes useful electrical components?
They prevent electricity from flowing in multiple directions and potentially damaging appliances.
Describe what happens when you rub a balloon in your hair.
Electrons in your hair jump to the balloon, causing your hair to become positively charged, and the balloon to become negatively charged
What does it mean for an object to be conductive? Why are some objects conductive, while others aren’t?
An object's conductivity is how easily it allows electric currents to pass through it. An object's conductivity largely depends on how readily it allows electrons to move around. Objects like wood and plastic do not share electrons very easily, and are not very conductive as a result.
List one advantage and disadvantage each for series circuits and parallel circuits.
Series circuits do not drain as much energy and are much less likely to overheat, and if a single component is disconnected the entire circuit does. Each subsequent appliance gets less and less voltage from the battery.
Parallel circuits will continue to function even if a single component disconnects, and each appliance gets full voltage from the battery. They drain much more energy and are more likely to overheat.
I make a parallel circuit using a 9-volt battery, and attach three light bulbs on separate wires to this circuit. How much voltage is going into each light bulb?
9-volts, because it is a parallel circuit.
List two differences between an incandescent light bulb and an LED.
LEDs are much more efficient
Incandescent bulbs produce heat
Incandescent bulbs use a resistant filament to produce light
LEDs only allow electricity to flow in one direction