EE 211_212 SP15 HW #02_sol -- Charge, Current, Voltage, Power, Energy, Basic Circuit Elements, Ohm's...

8/18/2019 EE 211_212 SP15 HW #02_sol -- Charge, Current, Voltage, Power, Energy, Basic Circuit Elements, Ohm's Law

1/13

18/V2015 EE

211/212

SP15 HW #02 -- Charge, Current.

Voltage,

Power, Energy,

Basic

Circuit

Bemente,

Ohms Law

e. E 211/212

SP15

HW 02--Charge,

Current,

Voltage,

Power, E n e r g y , Basic Circuit

E le ments, Ohm s Law

ftt? °o

Due: 6:00am on Monday, January 26 , 2015 >

Y O J

will receive

no

c red i t fonWms

y ou

complete afterthe

assignment is du e . _ .. _

Voltage a n d Current

Learning Goal;

To determina

thè uoltage

and

cu rrenls

fot dementa in a n eleclric

circuii.

In

etecinc

c i rcui ts . ali e lemenls

have a

vollage acrass Ihem and a currenl passing

ihrough

them. Al

its

mos l fundamental level,

vo l lage

re lales lo t hè energy

needed

lo

separate

charge

and

currenl relates

t o

thè speed

a l which

charges move.

In Ihis

tutorial.

y ou

will leam

lo

calculale

voltage and

currenl

(or

systems usirtg these fundamental

delimions.

Part A - Calculaling vollage

If it takes E = 3&.ìmJ ot energy io separale Q 0.56C

ol

c harge . what is iheresullanl vo l tage

Expre ss

your answ e r

to

tw o significarli figures

an d include t h è

appropriate unite.

You

d id

noi open hinls

(or Ihis pari.

A NSWER:

v

Part

B-

Calculaling

energy

Howmucherteray_does

il t ake

lo

separale

Q =

2.36;tC

of charge

if thè

vollage

is

V =

1.7mV

?

Expre ss

your

answer to tour significar ( igures and

include

(he app ropr iate

un i ts .

You did not open

hinls

(of this

part.

A NSWER.

F

2

3é

4.C 12 « J

Pari

C -

Ca lcu la t ing currenl

based on movement of charge

If

Q

r = 1.25C ol charge moves to ine

righi

in t

r

= O. ls

while Q

= -3G25mC of charge moves lo

Ih e lefl in ;

=

4.5s

. what is

th è

n el current lo th è righi"'

Expre ss your answer to two significarli f i g u r e s a nd in c lu de th è appropriate units.

+• —

m

m

•

You did not open hinls for this pari.

A NSWER


2/13

18/1/2015 EE 211/212

SP15

HW #02 -- Charge, Current, Voltage. Power, Energy,

Basic Circuit

Elements, Ohm's

Law

C/ t

Pari

Denve

thè

expression for

thè

charge that accumulates

al

thè upper

terminal

for /. > 0.

ANSWER;

O

q t) = 52.0f -* ' /iC

09(()=l30e * 'C

O,/(I)

1 30 1 • ^ ì

= 52.0 1 - e *)

- 30 e

ItooT

•

-Zioofr

PartB

Find Ihe lutai

diarie

ihal accurnulales al Ihe upper terminal.

Express

your

answer

to three significant ligures and include thè

appropriate

units

ANSVYER

,,

dt - -Jl̂

2SGOt 1

-

=

0 051

Pari

C

II thè current is stopped ai t =

0,4 ms .

how

much

cha^e has

accumulated at

thè upper terminal''

Express your answer to Ihreê significant

figures

and include ine appropriate units.

ANSWER.

£

.

O

^

Problem

1.10

In eJectronic circuits it is noi

unusuaf

lo encounter currenls in

thè

microampere range Assume a 34)tA current. due lo

ine

flow ol

electrotis.

Pari

VMiat is thè average number of

eleclrons

per second ihat

flow

past a

fixed

reference cross

seclion

ihat is perpendicular to thè

dreclion

oi

Express

your answer utingjwo significarli figures

ANSWER

4*

A x 4 ̂ I

« i«

4) Problem 1.14 B

Two decine circuits.

represenled by boxes A and B. are

connected

as

shown

in

thè figure.

Ttie relerence

direction

for

thè current

i

ni llie interconnection

and Ihe

reference

polanty for

thè yollage

n

aerosa

thè

interconneclion

are as

showti in

A

+ —

B

https://session. mas Ieri

ngengineering,com/mycUassignmenlPrintView?assignrnentlD=

1220572

2 a


3/13

18/1/2015 EE 211/212 SP15

HW #02 -- Charge, Current, Voltage, Power, Energy,

Basic

Circuit Elements, Ohrn's Law

P>o

p«wer

ur r

elemune Ihe power associaied wiih

Ihe

box B lor i = 7 A , v = 30 V.

Express

your answer

to Ihree,

significai»

fi g uree and include thè appropriate units.

ANSWER:

K

Pari

B

Stale

whether

I he

power is

flowing

troni

A to 15 or vice versa.

ANSW ER-

from A lo B

O

from

B

io

A

— Fi

r̂ > fro

Part

C

Determine Ihe power associaied wilh Ihe box H fo r i = -8 A. v = -20 V calculate thè power i n th è interconneclion.

Express your answer lo hree significarli

f igures

and include t hè

appropriate

units.

ANSWER

Delermine Ihe power associaied

wilti

Ihe

box

B for = 4 A, i; = -55 V .

Express your answer to three significar» figures and include thè appropriate

units.

ANSWER

p B

acerbe

State

whether ihe power is

flowing

from A to B

ANSWER

^J® fron A to

B

0 from B to A

Par E

or vice versa. ^

E> S4U

+

^

nbĉ \~> dorbCp

T 0

Stale whether Ihe power s flowing from A to B or vice versa.

ANSWER.

XmB to A

O

frani

A

lo

B

~>

A

6» fr> A

PartG

Oelermine t hè power associated wilh t hè box B for i= -9 A, v = 40 V. calculale thè power m Ihe interconnection.

Express your answer lo three significati figures and include thè appropriate units.

ANSVvER:

p —

Part_H_

Stale whether Ihe power is flowing from A to B or vice versa.

ANSWER

O from A to B

from

Sto

A

b

>̂

A

a^sork h £ r i lasci .

fi fu

\m

1.15 2

pv^

V

\s

ieri ngengi

neering.com/myct/assignm

entPrintView assi gnm

enti

D= 1220572

3


4/13

18/1/2015

EE 211/212 SP15 HW #02 -- Charge, Current.

Voltage,

Power. Energy, Basic

Circuit

Elements, Ohm's Law

When a car has

dead ballery, '1

can often be

slarterj

by

connecling

Ihe

ballery Irom anoiher

car

across iis lerminals.

The posit ive

terminate

are

connecied logelher

as are Ihe negative

terminala.

The

conneclion

is illustrateli m

he figure. Assume

Ihe current m he

figure

is

measured

and

ound lo

be 35A .

Part

A

Wnich car has t hè

dead

ballery''

ANSWER:

O

Ca rB .

A /a

U H re n k

C

C n a f t a

d; V f f » of f »

3//Wuu «/«.

J < V

b_ V t =

r̂

b4te7

ù

A

Z^ Car A

ha

^


5/13

Determine th è magnitudes of t hè total power

supplied

and

th è to ta l power

absorbed in thè

circuii.

Express your answers using

t h ree

significant f igure s s e p a r a t e ti b y a c o m m a .

A N S W E R :

•» snn i

_

abs ~

kW

Part

B

Poes

Vivi iwUrtOM £ctt


6/13

8)

Problem i.35 4

If

we

suppose that there

is no

power lost

in

thè wires used

to

distribute power

in a

typical home

we can use

thè

model

for thè

power distribution circuii shown

in

thè figure.

Part

The following wltages and currents are calculated for thè components:

v

b

120 V i

10 A

= 120

Vi f

= 3A

u

g

=120 V H

G

= ?

vh 240 V ih

7A

If

th è

power in this modified model balances what is th è \alue of thè current in component g?

xpr ss your answer to one significa nt figure and include thè appropriate units

A N S W E R :

Kci

tu

•


7/13

9) Calculating Power Using thè Passive Sign Convention 24

Leaming Goal :

To deiermine

Ihe

power of a circuii elemenl where th è tnttage across thè

elemenl

a nd Ihe cunent passing

Ihrough

th è

elemenl

are known.

In electric

circuits. ali elements ha\

a voliage across

them

and a

current

moung

Ihrough them. Depending

Od Ihe

reference direclions, thè element

couid be delivering or

absorbing

power.

In this tutoria , you

will

leam aboul power using t hè passive

sign

convenhon fo r circuii elements where t hè

collage

and current are known.

Part

- Voltage

drop

and currenl

direction

in an

ideai

circuii

element

Delermine

t hè

vollage v\d currenl

| |as

shown

m

hè

figutes below.

Assume

ihat

thè

voltage

drop

between

lerminals

1 and 2 is Vf =— 2 . 9 mV and thal

t hè

cun-enl

enlering

terminal 1 s /* = m

Express your answ«r totwo significar figuret, wiih appropr ia le unite.

You did noi open

hinls

to r this

pari

A N S W E R

_\

0)

(a)

Pari

B - Power calculation for an ideai circuii

element

Th e circuii elemenls shown have

a vrtlage

between terminals

1 and 2 of

V T =

5.8 V. A cunent ol

T

=

-0.90

inA

enters terminal

1.

Calculate

Ihe

power absorbed (positive quanlily)

or

supplied (negative qua nlity) b y eacri

circuii

elemenl.

E x p r e s s y o u r a n s w e r lo

Ihreesignificanl

f igures, w i t t i

appropriate

unils.

You did

noi

open hmts for this

pad.

A N S W E R .

T/U


8/13

i - -0.90 mA

V- -5.8

V

V - 5 . 8 V

i - 0.90 mA

a

v^S.SV

?

hr

•

-

r

f

Pgrj

C •

Balanang power pari 1

A circuii consiste o f f i c e clemente. How much power is dissipaled of deh\ered by elemenl 5 if element 1 is

deji\ennaP|

= 660m\ of power, element 2 is absorbing A =

490ni\Vof

power, elerneni 3 is absorfaing P-

= l_13niW

of power, and element 4 is dehuenng P

=

^30mW ol power.

Express your

answer

wìin

thè appropriate unite

You did noi open

hmts

ftx ihis pari.

VjUi£rvJ

— >

O

ANSWER

50

P3 —


9/13

P

4-

A

= 5.2.

\X/i

w

4

«4= .

.»

(.4

ar t

. tU fĉ aUr̂ or 0.fi««J W

Prob lem2.11

Consider Ihe circuii showii

m

Suppose Ihal

i s

= 29

m

A .

f

Pi

ParjA

Fihd

v

for thè

Circuit

m

t hè figure.

Ex pr es s your

answer

lo three significati figures and

include thè appropriate

units.

A N S W E R

•

•

i,


10/13

V

P a r t B

Find Ihe

BQwer

absortied b y Ihe reaislor (or Ihe circuii

in

t hè fgure.

xpress your answe r

o

lh r e e _ i g n i li c an t ligures and include thè appropriate units.

AN SWER

5

IV

Part

Re\erse

Ihe direction ol Ihe

cuneni sojrce in

t hè circuii shown in Ihe figure and firid or a new Circuit.

Express

your

a n s w e r to t h r e e

signiflcanl

figuresand

include thè appropriate units.

AN SWER

\ /

o V

P a r t o

th è tìireclion ol

Ihe current

source

lor

Ihe circuii shown

in

t hè figure and finti t hè power absorbed by th è

resistor

for

Ihe

new circuii.

Express your

answer

to three s i g n i f i c a

ut

figuresand include Ihe

appropriate

unita.

ANSWER

v

t

Problem2.13

A pair

o

automoli*

headlamps

rs connected lo a 12 V

batlery «a

Ihe arrangement shown m . In Ihe ligure, th è

tnangular

Symbol is used lo indicale t ha t Ihe terminal is connected directly to thè melai frame ol t hè car.

ni p

Pari A

Conslruct a circuii model usmg resislors and an independent

Collage

source. Idenlily th è correspondence between

th è

ideai circuii

elemenl

and

th è symboi

component that il

representa.

Drag

thè

appropriate labels

to

their

respective

t a r g e t s .

AN SWER


11/13

i

•

n

•

,V,

i

swilcli

resistane^

of Ihe

ìa ' r i p

i

esistane

- of hi; i im I;

ninnai

r->'imiaf .;e > > l

he bdtierv

no- load vedati» 0 1 hè -iait*-rv

i

^

1

III-: ictrilj.

A

esisiance

of thè «it between

ihfe

<

. • - . . -

I

' . i r ' 1

l

osa

Problem2.15

A

uarieiy

of \dlage source uelues

were applied lo

thè

deuce

shown in .

Part A

The power absixbed by Ihe

deuce for

each «lue of collage is recorded in Ihe lable below. Use th è «lues in thè t aW e lo construct a circuii rnodel for Ihe tleuce consisting of a single

resistor rCMn Appendix H m

th è

lexlbook.

Delermine th è resisìance ot th è

de«ce.

Ex p r e s s y o u r a n s w e r lo tw o s ignifica ni figuresand include thè appropr iate

uniis.

ANSWER

Electrical Resistance

Learn i ng Goal


12/13

To use Ohnvs law lo calculate

thè

«dtage acrass. thè currenl through, and thè power d iss ipated

labsorbed)

by res is iws.

On e o (

Ihe masi common eJements in eleclnc c ircuils

s

th è resistor. Th e «Jltage across an d Ih e currenl Bowing Ihrough a reaislor a re related lo each other «a Ohm s law. In Ihis lulorial.

yo u wll leam

how to apply Ohm s law to calculate uo ltages, currenls. and powers

^

Calculation

o f

vgltaggj

currenl.

and power

to r

a

r es is to r

and a

conductor

Usmglhe twoc ircu i is be low, calcinale IL

, 1 2 . l i . «2 .

thè power

P^ being

dissipated (absorbed)

by Ihe

resistor,

and

th è co nductance

Pc/i.

Assume thatj

-

2 . 7 A , V

t — .5 V

/?

~

270

Sì.

and

C =

0 . 2 7 S .

E x p r e s s y o u r a n s w e r io tour signif ica ni

f igure

s . Use thè

drop-down

menu to choose units.

You did

n oi

open

hinis to r ihis pari.

A N S W E R

2

ìoo

A

R - i

t

r

(ito

L

3

A

=

=

O.4050A ---4o .0

Pati

B

Anarys is of a circuii containing a vot tage source and resistor

In

th è

circuii below, thè \dtage source supplies

P - 350

tnVV

of

power

and thè

currenl

flowng Ihrough

th è

resislot is — 150

mA. Calculate V

and R.

Express y o u r

a n s w e r

lo th ree

significaot ( igures.

Use thè

drop-down

menu to choose

unite.

Vou did

noi open

hints for

this pari.

ANSWER

- R T ^

> V ^ 2 3 5

v

=

/ = 150 mA

y.Q

R*>V

vh

\z


13/13

art Analysis

of a

circuii conlaining

a

current source

and a

conductance

Q 0 -05 S and thè power being

deli\jered

lo Ihe conductance

is

— 0.25 W. determino V and /

Expres* your

a

nswer lo

Ihree

significa ni

figures. Use

Ine drop down m e nu

to choose unils.

Voti did noi open

hinls

lor Ihis pa d

ANSWER

w A -

Score Summary:

Your score on this assignment is 0.0 .

Vo u

receiued Oout

olà

possale

loial ol 10 0

poinis.

EE 211_212 SP15 HW #02_sol -- Charge, Current, Voltage, Power, Energy, Basic Circuit Elements, Ohm's...

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Transcript of EE 211_212 SP15 HW #02_sol -- Charge, Current, Voltage, Power, Energy, Basic Circuit Elements, Ohm's...