Physics test 7th grade #3 Flashcards
What are the three basic features of an electric circuit? (key concept)
The three basic features are:
Devices that run on electrical energy
Source of electrical energy
Conducting wires (leads)
Give two examples of energy sources
Battery and power pack
Which way does the current flow?
From the positive end to the negative end
Does electrical energy get used up? Explain
Electrical energy doesn’t get used up because it just turns into a different form of energy such as heat,m
What do conducting wires allow the charge to do?
The conducting wires allow the charge to flow from the energy source to the device that runs on electric current and back to the energy source
What component is used to shut off devices?
A switch is usually used as a shut off device since it breaks the circuit
What is a series circuit? Explain
A series circuit has one path for the current to take. If one light goes out then there will be no path for the current to take, making all the other light bulbs go out too. If you add more bulbs without changing the voltage settings of the power pack then the other lights will burn less brightly. They will get more and more dim as more bulbs are added on.
What is a parallel circuit? Explain
A parallel circuit has multiple paths for the current to take. If one light goes out then the current will take a different path and continue to light up the other bulbs. If you add more bulbs in a parallel circuit without changing the settings on the powerpack, the brightness of the bulbs is not affected.
What is kirchhoffs first law?
The sum of currents flowing into the junction is equal to the sum of currents flowing out of the junction. Basically whatever goes into a circuit must also come out.
What is kirchhoff’s second law?
It states that around any closed loop in a circuit, the directed sum of potential differences across components is zero.
Basically that the sum of all voltages around a closed loop in any circuit must be equal to zero.
what is the symbol for a lightbulb? A battery? a Switch? and a lead?
A circle with two lines through it in an x shape is a bulb. A battery is two lines next to eachother one slightly shorter than the other. A switch is a line with a break in it, and a lead is a straight line.
