Unit 7 Electric Circuits Current Electricity the rate

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Unit 7 Electric Circuits Current Electricity

Unit 7 Electric Circuits Current Electricity

the rate at which charge passes a point Current I is _______________________ Ex. 22

the rate at which charge passes a point Current I is _______________________ Ex. 22 C of charge pass a point in 4. 0 seconds. Find I. I= Units: 1 coulomb/second = 1 ________ 1 C/s = 1 ____ So the answer can be written I = ____

Physics Reference Tables, page 3: top

Physics Reference Tables, page 3: top

the rate at which charge passes a point Current I is _______________________ I =

the rate at which charge passes a point Current I is _______________________ I = Δq / t Ex. 22 C of charge pass a point in 4. 0 seconds. Find I. I= Δq / t = 22 C / 4. 0 s = 5. 5 C/s Units: ampere 1 coulomb/second = 1 ________ 1 C/s = 1 ____ A So the answer can be written I = ____5. 5 A

fundamental Amperes are ___________ units. (m___sk)A derived Coulombs are ___________ units What is a

fundamental Amperes are ___________ units. (m___sk)A derived Coulombs are ___________ units What is a coulomb written in terms of fundamental units? 1 C = = A·s Ex. How much charge passes a point if the current 0. 25 ampere for ____seconds? 3. 6 at the point is _____ I = Δq / t 0. 25 A = Δq / 3. 6 s 0. 90 A·s = Δq 0. 90 C = Δq

Don't forget that the amount of charge Dq passing a coulombs, C point can

Don't forget that the amount of charge Dq passing a coulombs, C point can be written with units of _________ elementary charges, e or _________________. The conversion from one unit to the other is found on pg 1 of Phys. RT: 1 C = ____________ e or 1 e = ____________ C Ex. How many electrons pass a point in 2. 5 seconds if the current at that point is 0. 50 A?

Page 1: top

Page 1: top

Don't forget that the amount of charge Dq passing a coulombs, C point can

Don't forget that the amount of charge Dq passing a coulombs, C point can be written with units of _________ elementary charges, e or _________________. The conversion from one unit to the other is found on pg 1 of Phys. RT: 6. 25 x 1018 1 C = ____________ e -19 1. 60 x 10 or 1 e = ____________ C Ex. How many electrons pass a point in 2. 5 seconds if the current at that point is 0. 50 A? I = Δq / t 0. 50 A = 1. 25 C Δq / 2. 5 s = Δq 18 e 6. 25 x 10 1. 25 C x ----------- = 1 C 7. 8 x 1018 e

at least 2 things. To have current, you need _________ A potential difference a

at least 2 things. To have current, you need _________ A potential difference a voltage source) 1. ______________ (aka ______ cell a/ a ______: neg. (-) _____side or low _______ potential wire pos. (+) _____side or high _______ potential wire two _________ different metals voltage depends on the metals used. The amount of ______ more than 1 b/ a battery = ________cell: more voltage more cells _________ generator c/ a _______ :

Physics Reference Table: page 3 bottom left:

Physics Reference Table: page 3 bottom left:

energyto a circuit by A voltage source V supplies ______ an electric field setting

energyto a circuit by A voltage source V supplies ______ an electric field setting up ______________ within the circuit. low pot. _______ flow of electrons ____ ( e- ) + high _______ pot. V magnified wire cross section flow of positive ______ charge negative "-" side of V. Electrons flow out of the ________ + V. This is equivalent to flow of ___ charge + out of ___ side of atoms The e-'s collide with _______ of wire. This absorbs electrical energy and _______ heats _________ the up wire. fast between collisions is ______, The speed of e-'s _______ but the. drift (________) velocity of e- is _____ slow. or average

"direct" current Batteries supply a constant V _______DC I charge moves in 1 direction

"direct" current Batteries supply a constant V _______DC I charge moves in 1 direction only __________ t Generators supply a varying V ________ alternating current AC ______ I one direction charge moves in _________ t other direction charge moves in _________ In Regents Physics, we will mostly study _____ , DC but the basic ideas are also valid for ______. AC

Edison tried to prove that AC was more dangerous than DC by electrocuting animals.

Edison tried to prove that AC was more dangerous than DC by electrocuting animals. Later, he helped develop the electric chair. 1903 Topsy dies.

William Kemmler murdered his common law wife Tillie with a hatchet. “Chaired” on August

William Kemmler murdered his common law wife Tillie with a hatchet. “Chaired” on August 6, 1890

Sizzlin' Sally, Old Smokey, Old Sparky, Yellow Mama, and Gruesome Gertie.

Sizzlin' Sally, Old Smokey, Old Sparky, Yellow Mama, and Gruesome Gertie.

complete 2. A ________ circuit Ex: battery + switch wi Using circuit symbols: V

complete 2. A ________ circuit Ex: battery + switch wi Using circuit symbols: V re light open circuit ____ no current Switch up ______ "complete" Close the switch ______ closed circuit _______ current charge flows _______ Can you have voltage without current? yes Can you have current without voltage? no

ammeterwhich Current I is measured with an _________, digital multimeter is often part of

ammeterwhich Current I is measured with an _________, digital multimeter is often part of a DMM (_______________ ). Its symbol is: wire A wire In an electrical circuit, ammeters are connected "in series" _________. This means the circuit must ammeter opened up be ________ and the ________ must be _______ into it: inserted w/o ammeter: Circuit _______ circuit part 1 circuit part 2 Circuit _____ with ammeter: circuit part 1 circuit part 3 circuit part 2 A circuit part 3

DMM

DMM

voltmeter which Voltage V is measured with a _________, DMM Its symbol is: is

voltmeter which Voltage V is measured with a _________, DMM Its symbol is: is often part of a _____. V In an electrical circuit, voltmeters are connected "in parallel" _________. This means the circuit is _______NOT opened up , but the ________ must be voltmeter connected _______ across two points in the circuit: Circuit: V circuit part 1 circuit part 2 circuit part 1 circuit part 3 circuit part 2 circuit part 3

Ammeters measure the current that passes ______ through a part of the circuit, in

Ammeters measure the current that passes ______ through a part of the circuit, in other words, the amount of charge through ______ each second that passes ______ it. potential difference Voltmeters measure the ______________ from one side of a part of the circuit to the other side. "across" the circuit part. This is called the voltage _______ energy needed to work or _______ It represents the ______ coulomb force each ________ of charge through. In symbols: V circuit part in parallel I A in series pot. diff. affect the Ideally, neither ammeter nor voltmeters _______ circuit in which they are placed ________________ , but in reality they do.