This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: PIiY 2426: Engineering Physics 2 Exam 2H: l3 March, EllDE Name: LIE DU SSH: :2 i} (ll) (Last 4 Digits} ._. I) A small metal sphere of radius, r, = 20 mm, initially,r has a net electric charge, Q = 165 ME. A second larger metal sphere of radius, r: = Eﬂﬂ mm, initially:r has a no net electric charge [i.e. net charge of zero). The centers of
the two spheres are separated by a distance of d = lﬂﬂl) nun. rl=2ﬂ mm : exit} I“ % r3=200 rnrn : D n W. What are magnitude (11C) and s_igg (+f—} of the net electric charges on each sphere (q, and :11) respectively after [hey are then connected by a thin
conducting wire“? lCaution, use Si units. r J"
«a : t s Wth ,2
l l_ (ill I {i1 ’jl Cir. / l
a: — —I— ‘_—I F: —' : L 5 —_
IRE]. {TLff. {it EF’ :11 F1 In . i __ T I q: i __ .+ l J : rﬁ r/
h“; l1; L is; J /
\R. _
s'} r111 _ Q _ t F1 ' L— :I/ “3" ﬁt' (—3. 2 ) 2 lg?) _."" _‘ "' n4, .' —— ——~—._
' L: {1‘ II I” " F; 1 ' j '
t I ’
K h l2" XI ill" Hat .1! e' J 'l' J1
J l? ——— __ {j / ______ __ l j _, C I
,1 _ LO l if I F _ L P A J
l p IJ I n X 2/}, "l "E." 2.) Answer the feliewing questions regarding the circuit below, r _ i i ,_ i
“1:. I ii‘ ii? if}
.J'l‘ : Earext T " i2r:
—" Rikr  rd £13 I
_ g  m : 2a) What is the equivalent resistance, R,” , ef the circuit?
x7 i941 ; 1'2 jL/ W lb) What is the tetal eurrent, IT , through internal resistance, r '? Hint, use Ohtn’s Law, I. = 8.me . t , L /
I : Flam ‘— 1: is] What is the terminal veltage, VT '5’ _
"I, _— t1“. —:r.t': 53’ : 5V 1d) What are the branch currents, II and I: ? Hint, note what the veltage is aeress
eaeh resistor, then applyr Olim‘s Law. j I __ : : 1l' : W _ : — _,]_ /
.I I   5,: ' .I' la) What is the pawar dissipated in all three resisters, P, , Pl , and P3 '? , _. r_ .3. i __ !
Fr 3” {Ti : 19” "ii : r'T' ,‘Th‘i/  ...— 1i
tfi' "r 1: Fl : 1: 1—3 ": —_' r, —_ : :3 / 1%? 3a.) What is the equivalent resistance, Rah , ef the fellowmg network if all
resistere have the same value: R = 2!) KS7. ‘? r" 1
.3 T7, L'fLy/ 31:.) What is the equivalent capacitance, Cal, , of the following network if all
eepaeimrs have the same ‘value, (3 = 2 HF ‘2'
F Q; Len: : —
“FtIre. W / M 4a) What is the capacitance, C = ?,of the following parallel plate capacitor, where
the plate separation is, d = 5 mm, and radius of plates is, R = 5E} mm, and
glass is between the plates {tt = 4.5)? Note, r‘trea of plates = rtR2 . Caution, use 31 units. _ TTTL
_— : Kt: #— : &.'2am"HF "" 3 4.13] Assume that there is no net charge (q=[l) initially on the parallel plate
capacitor. At time t={}, the switch (SW1) is closed and the parallel plate
capacitor begins to charge. When completely charged, what is the maximum charge qr,“ on the capacitor? .. W a ﬂlhhjwlf; C if _" [IEQyLGFH— : {:"?,5 3‘3"]— (3 : 3.15xlo'”¢ 4c] What then is the value of the electric ﬁeld, E in Wm, in the gap?J y /
_ i F . : iii"m 1 5i 3 fl “3 m 4.d) 1What is the work , in Joules [l], done by the battery to charge the capacitor to
a maximum charge qmm? Hint, this is the same as energy stored in capacitor. l} T .rfll'tr'___ Gaff3 .r of i : [y3_ Et’ at I503— ' W or _.. "1‘3 l a PD J 4.e] Which plate is positively charge¢@g'r Circle choice here.
... 1/ 4 5a} A parallel plate capacitcr cf plate area (A) and plate separaticn (d) is ﬁlled
With two dielectrics, K1 and K2 , of equal area (NE). Shcw the capacitance is given by
C { K] r //
.[ : I I _.— n
ct
(Hint. Think of this as two capacitch in parallel.) _._r*___" I
:11 MF/‘ﬂl ,_ C +1 / 35:
x J] a" 'l'
‘—t—' r' a u arts ’55: Mei:
;'}__ ——~ll— _ fl Cl
.‘H "n.
’a ,: ‘2 “Manual
*1 'k: 1— l: I'l ——' “mg l I _ _'_ Ilk “'1
_ T— l a " ." k all 9 5b) What must he the diameter cf an iron wire if it is to have the same resistance,
R, as a ccpper wire 2.4 mm in diameter. hcth wires being the same length L“? Use 31 units! Hint, set RFE = RC“ , then preceed. E
Area = m2 ={ed1y4 '20
pa" = 1.69 x HIE $1111 a”
pa: = 9.36 x 10“: ﬂmJ
Elm, = 2.4“ mm Ella; 3 l(Jr‘ ﬂ _ K‘Ea
‘1 IL— I ll ' I'D
r” F— : PE? :— 33. Pm; 'T l_ in??? I] 1
A Ili—li—IlpiClr‘ijlh—F I. JigE?)
l"I r: _' PF Pr" A
l l‘ — a a _ i — I" s. l t  : : " “l
1’"?T 0* ' J A“ l j" PM a;
ﬁlm 'gilrw FISH '
J. ‘F _ ’ .31, _ q “I / :I [— ﬂjrle)* “Lie 3'1 £175 )4"
clef: \ I an r— 5 ll
—
a
Cr:
{:6
K ...
View
Full Document
 Spring '08
 Ronald
 Electric charge, Parallel Plate Capacitor, net charge, small metal sphere, parallel plate, net electric charge

Click to edit the document details