Circuits Review Flashcards
Capacitor
Rheostat
Resistor
Wire
Battery
Switch open
Switch closed
Anmeter
Voltmeter
Lamp
3 components of a simple circuit and draw it
Battery, load, wire
Series differences:
— - Individual lamp voltages add up to battery voltage voltage divider
- Current is constant.
- When one bulb is out all bulbs go out
- More resistors means higher resistance and lower current
Parallel differences:
- Voltages are all the same
- Lamp currents add up to battery current
o The lamp furthest from the battery had the least brightness - One bulb went out, rest stayed on
- Current increased and resistance decrease with more bulbs/resistors
Resistor codes:
Black = 0
Brown = 1
Red = 2
Orange = 3
Yellow = 4
Green = 5
Blue = 6
Purple = 7
Gray = 8
White = 9
What are the 3 ways to charge and object?
Through friction, contact and induction.
Why are you safe inside a car if it was struck by lightning?
Lightning hits a car and seeks to travel to the ground, and all the electrons are repelled by each other and want to get away from each other. So it keeps to the exterior metal cage of the car instead of going straight through and exits through a wheel into the ground. This is called a Faraday cage.
- In the first circuit above, which of the three resistor(s) has the most current passing through it? Explain.
The 8 ohms resistor, because it’s a series and therefore divides voltage so it has more current than the other two that are parallel and have current divided amongst them.
- In the second case, which resistor(s) has the least current passing through it? Explain.
All the resistors in the second case have the same amount of current passing through them, it’s being equally divided through parallel and then transferred in series.
- What is required for current to flow?
A difference in voltage.
- Why can birds and squirrels sit on a 50,000V power line and not get fried? (Think about question 8.)
The bird is sitting on the power line and there is no difference in voltage because they’re not touching any other power line, so electricity doesn’t move through the bird.
- Which bulb will glows the brightest in the circuit to the right? Explain.
The 5 ohms the furthest to the left, it’s in a series circuit. Series circuits have
greater brightness when they have less bulbs. It’s current is also not being
divided like the other two are.
- What is a rheostat and where is an example of one in a house?
rheostat is a variable resistor. Light dimmers are rheostats.
Why does lightning occur?
Clouds rub against each other in a storm and become negatively charged. The attraction between the cloud’s electrons and the ground’s neutral charge grows strong enough until the electrons jump down to the ground in an attempt to equalize.
