PH~NG
GD&DT
LONG
BI~N
KY
THI
HQC
SINH
GI~I
QUAN
NAM
HQC
2012
-
2013
Men
thi:
V@f
El
Thai
gian
lh
bii
:
150
phit
Ng&
thi
:31
thkng
01

sui
diy
mM,
nhe,
khbng
co
d&,
thA
trong
nuuc
(Hinh
1)
.
Kh6i
1uWg
ri&ng
cua
qu~
ciu
bbn
tr&n
la
D~
=
300
kg/rn3,
kh6i
lugng
ri&ng
cua

~h$
tich
phhn
nh8
1Bn
khbi
mat
nudc
cim
qu8
chu
phia
trh
khi
he
v$t
Hlrh
I
cbn
bhg
?
2.
Lpc
cang
cua
sqi
diiy
?
Bhi
2

thi
sau
thbi
gian
tl
=
10
phut
nukc
s8i
.
N$U
dhng
bep
dau
trdn
dB
dun
sdi
m$t
lugng nubc
c6
khbi
lugng
m3
dung
trong
dm
tr@n
trotlg

=
4200JIkg.K
;
c2
=
880Jkg.K
va
nhiet
luwg
do
b&p
dhu
toa
ra
m6t
cach
d&u
dgn
.
Blli
3
(4
bi&r)
Cho
mach
dien
nhu
hinh
2.
~i6t

Xac
dj11l-1
s6
chi
cia
van
k6
khi
con
chay
C
&
chinh
giBa
MN.
Tinh
cang
sdt
toa
nhi&
tren
bi&n
trb.
2.
Xac
djnh
vi
trl
C
trCn

8R
;
R2
=
R3
=
4n;
%
=
61r
:
UAB
=
6V
khdng
bdi.
Dien
tr6
ciia
arnpe
k&
,
kh6a
K
va
cac
diy
nbi
khBng
dkng

Khba
K
d6ng
.
2.
Xet
tmhg
hqp
khi
K
b6ng
:
Thay
kh6a
K
bing
dien
trb
R5.
Tinh
R5
d&
cuhp
de
dhng
dien
chgy
qua
dien
trir

gbc
viri
trgc
chinh
ch
mat
thiu
kinh
hQi
tu
,
A
nim
tr@n
tryc
chinh
(
hinh
4
)
.
Nhin
qua
th$u
kith
ngubi
ta
th&
MI
AB

sau
:
1
-
11

OF
0.4
OA'
Khi
miu
blit
chi
djch
chuykn
da:
theo
t~c
chinh
lgi
thiu
kith
thi
a0
ch
n6
djch
chuy&n
theo
chi&

nhon
B
cb
nb
huhg
thhg
v6
quang
t&m
0
.
'Lai
nhin
qua
thhu
kinh
thi
thhy
Anh
c6a
but
chi
ciing
n$m
doc
theo
tryc
chinh
d
co

Anh
b
clia
A
qua
A'
F
A

thku
khh
,
F
lA
tie~
dihm
v$t
cclia
thhu
kinh
X
Y
(hinh
5).
in^
phCp
v&
,
My
xhc

.
.
.
. .
.
.
.
. .
.
. .
.
.
. . .
.
.
.
. .
.
. . . .
So
bcio
danh
.
.
. . . .
.
.
.
.
.

,.,., ,.
Lb;
2,,, , ,.,
*.Chi2
ki
cia
gidm
thj
2

,
.,

,