$18(1+54%)
8.12
Selling price of the
日四十月三年九七九一层公年八十六國民奉中育教僑華
Cost price of the article
(a) Volume of water
in the pool
ŝx(15+6)x20x12.
900 cu.m.
article at a
of 40%
(b) XR =
(6–1%)m
$12x(1+40%)
tand
$17
Salution:
買四第張十第日六十月二年未己鹰复
WAH KIU YAT PO (i) the resistance of B
報日僑華
三期星
1979
中學會考試題預習專欄
(ii) the current through B (b) The resistance of Bis
now measured. by using
of
specific heat capacity
opper - 420 J kg.
數學
(十三):
明德出版社文長波提供資料
Wheatstone bridge circuit
物理
(廿三)
as shown in figure 4.
明德出版社碁榮家提供資料
PHYSICS (23).
Mathematics (23)
Solution to Exercise 10
Section A.
Exercise 12
Magnetism
Solution
Electricit and Atomie. Physics
1. Two resistance coils X
and Y are connected to a
slide-wi
Wheatstone brid-
ge in the usual way and a balance is obtained when the
eliding contact is 0.3m from
the left-hand end of the wire (see figure 1).
(Wheatstone Bridge
Figure 1
The resistances X and are now interchanged and balance is obtained with the slider 1.2m from the left- hand end of the wire (see figure 2)
Figure
Determine
A.
the length of the wire (b) the ratio of X and Y
In figure 3, the driver cell E has an e.E.f. of 2.OV and negligible inter- nal resistance. The slide. wire is im long and
resistance of 20
Figure 4
The standard resistance S
is 120 and PQ is a uniform
resistance vire of length 1 m.
Cell & has an e.m.f. of 3y
and a negligible resistance
The bridge is balanced when
PX is 40cm. Using these data,
calculate
(1) the resistance of B (ii) the current passing
through B when the brid-
ge is balanced. (iii) the power dissipated
by B when the bridge is
balanced:
(c) Explain why the values
for the resistance of B obtained in (a) and (b)
are different.
A copper voltameter of
resistance 20 ohms and a
heating coil of reaistance
10 ohms are connected în
parallel across a battery. The coil was completely
immcrsed in 0.5kg of water
in a lagged copper vessel
of mass 0.5 kg. It is found that 8.91 x 10 kg
of copper is deposited in one hour.
·Coil
لتا
Solution:
20 cm
k-d'
(AOB – 2(5)-4
1080
[AON=/NOB=
AN NB
1089
Radius of the
Solution:
em 10 cm
The floor is inclined
at an angle 12a
the horizontal
Let radius of the
cross-section
(7.5-r)m
3m
AC=
LOCA - 90°
SN = √202+(41)2
20.5 m.
Area of the floor and
the four vertical
20.5x12+1x12+2
(1346)x20+6x12 sq.m.
486 sq,4,
Cost of the
480x704
$340 (correct to
nearest $
56.25-151
65.25
4.35
The radius
cross-section
Solution
(1_tanx) + (1+tanx) (1+cotx)" + (1-cotx)2
35 m.
work
10. Solution: Let xcm and ycm
be the lengths of the other two sides of the triangle (a) x+y= 19
—2tanx+tan x+1+2tanx+tan
from (2) x=
(3)
2cotx+cot x
Put (3) into (1)
10
17.01 cm
2+2tanx
CD is the tangent
of the circle åt [CAB= [BCH "[ACR= 90°
[CAB+/BCD+36° = 90°
2/CAB+30°
CAB = 27"
Solution x
(1)
(2)
The lengths of the
remaining two sides
from (1) x= 1+2
(3)
of the
Put (5) into (2)
(1+2y) y-y =
cm and 9
riangle ar
9 cm.
When y=2;
When
(b) x+
(2)
Figure 3
With K open, the balance
length x is 0.8m
(a-) What is the
of the
cell Eg
(b) What will the balance
length be when K is closed ?
An electric bulb B consumes
200J of energy per second when connected to a 200v
supply at its operation
temperature, Find
Calculate
(1) the current taken from
battery.
the
(ii) the heat energy given
out by the coil in the
same time,
(iii) the rise in temperature
of the copper vessel and
its content
(e.c.c. of copper -3.3x107.
-1
kgC specific heat capas
city of water - 4200 J kg
Solution:
Let $x be the sum
of money of the man.
His five daughters received $(1-2)(1) ►
or $
5 16
The fraction of the
each
money that
laughter received
5. Solution
攤提防假容
Section
Solution
(EUG) ******
每段大字四個 細字卅四個 每天四元
「支集」二字韃去(竹郵票請用二角害爲荷
10 10
讀者諸君: 崔荷李活道F號華僑日報廣告邵收賞即委爲刊登。 林成如需要刋登「經商小庆告」請將廣告文字列入表格沐同廣告實邸 元請將下列稿件由
華僑日報謹啓
#
日刊登華僑報分類小告
KOE
月
此致
WEET SHE
「九七八年
日
3
74 210 6 5
from (2) y= *
Put (3) into (1)
(x+10
19 (rejected)
幸運R
3-707036:4
3-708019!
永醫
通
九龍:
搬理公司
MË MUZI
5-704084
5-705074
搬屋公司
【業興
太小歡迎
|04|3–957235
92342433-922889
922307
5-221583
單人房 双人房小家庭 40元60元80元
搬屋公司專鐵 鋼琴土廠字楼
21.383792) 4331194
KASER -635357
80120631892
吉祥
The lengths of the
remaining two sides.
of the triangle are
6 cm and 9 cm.
永腿信 搬
門屋
【双人房80元 小家庭120元
-379430
848767 369569 436103 848480,368783, 135123
運
專門屋
古美女 龍運當
K)
三人房羽毛叶家延120元
3-631749-634114
5-629921-625822
980033
9698-17
**:957351
958805
誠友李學展公司 順風 50
3-952870 平安
3-951013 **
买九折30元 大小徽蓬
4:952375.958805
4:969033 969617 大角咀:957351.大小袱通
陳涉1
mexic
**
671482)||*. = 7906152
671945 FIE 35
691892 35
HEL ·· 672837 wi
763921
775720 204257
3 - 7412007
4 0 5 6 19
5
499366
運有限公司
注
Y
718177
718469
2 622834
T A4 62 2 8 6 3
# 944231
R4 944232
惠刊本報分類廣告
請撥電話