Study Physics Chp. 1719 Review Flash Cards

 
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Physics Chp. 1719 Review

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What is the equation that relates current, charge, and time?
I = ΔQ/Δt
What does power represent in the traffic analogy?
packages delivered per unit time
What is the equation that relates current, voltage, and resistance?
I=V/R
What does voltage represent in the traffic analogy?
steepness of the hill
What does current represent in the traffic analogy?
amount of truck passing per unit time (traffic flow)
What is the equation to calculate resistance?
R = ρl/A
What are the units for resistance?
ohms (Ω)
What is ac? What devices use ac?
alternating current- current that moves back and forth.

Devices that are plugged into a socket.
What is dc? What devices use dc?
direct current- current that moves in only one direction.

Devices that use batteries.
What is the equation to calculate power in a circuit?
P=IV
What is the unit for power?
watt (W)
What is power?
Energy used per unit time
What factors affect resistance?
type of material, length, cross-sectional area, and temperature
What is the unit for potential difference/voltage?
volts (V)
What is the unit for current?
amperes (A)
What is current?
amount of charge passing per unit time
What does it represent in the traffic analogy?
trucks
What is the unit for charge?
coulombs (C)
What materials are usually conductors?
metals
What is a semiconductor?
An object that can act like an conductor or insulator
What is a conductor?
An object where charges are free to move
What is an insulator?
An object where charges are not free to move
What is polarization?
When one side of an insulator is more positive and the other side negative resulting in a neutral object being attracted to a charged object.
What are the ways that an insulator can be charged?
friction and contact
What are the ways that a conductor can be charged?
contact and induction
What are the 3 ways to charge objects?
1. friction
2. contact
3. induction
How does a positive and negative charge interact?
attract
How do two positive charges or two negative charges interact?
repel
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