日五勒月四年日乙麼寬
WAH KIU YAT PO.
九
題類營專欄
物理科 (廿二)
陸永熾·
(22)
dy Mr. Lak_Wing Chee
Solution
(a) Paraday's Lava of Electrolysia.
Law 1,
The mass of any substance liberated during electrolysis in proportional to the quantity of slectricity passed through the electrolyte.
Lav 11 When the same quantity of electricity pass
through various electrolytes, the masses of the different substances liberated are proportional to their chemical equivalents.
An electrolyte is a substance (liquid) which conducte current and undergoes decomposition.
(i) As the distilled water in- not an electrolyte or conductor, no current passes in the circuit The bulb remains unlits and nothing happens in the liquid.
L
(ii):Mercury in a conducting Jiquid but not an electrolyte.
The bulb is lit an current paseas while the mercury in the glass vessel does not decompose.
Theory
日期
甘五月五年五六九一层公年四十五國民洋中
Circuit diazsan
idge
(unknown)
The metre-bridge consiste
of a straight uniform rearstance wire AB, 1 metre long, stretched over * borwood scale graduated in millimetres and mounted on a board. The enda of the wire are soldered to two stout) copper stripa e and c, and a third and longer atrip b In screwed to the board parallel to the wire,
If the keys K is pressed and the sensitive gal= vasometer G gives no deflection, (this is ensured by moving the contact jockey J along the wirel, then
pid, across R = p.4. across the length ad
dernos 5 = pide across the length, ES,
d. = current.
1
dividing
k/s
where.
(a):
(iii) Dilute sulphuric acid fu an electrolyte. It conduct's current as well as decomposen -into-II, and SO ione, drifting
tovarda-the cathode and anode where they discharge and set
and 0, gas respectively, The electric bulb is lit an' current passes.
free i
the unknown resistance R
Sx P/4
S • readings on the resistance box
the length of wire Ad
■ the length of wire dB
(b) From the above derviad formuls,
Jength Ad length, dD
To convert such, A LOW-TEBistance `meyer
育教佳業
voltmeter, a resistance must be inserted in seriee with the circuit,
At full-scale neriection, the_p.d.-paroną the]
meter la given by, V,
V. 0,015 x 5
'Since total p.d. across the whole is V
(V being the across the resistance added)
V1 = 0.015 k
60.075
5.925 volt.
»"resistance added in the circuit,
5.925/0.015
• 395.
Ans. The resistance is 395 ohms and is in series'
with the meter.
yuestions (23)
volta
1. (a) Describe how you would compare the em.f.s of two cells
using a slide-wire potentiometer.
(b) What are the precautions made?
(e) on what factors does the heating effect of a current dependy
(d) a 250-70it electric immersion heater 18 usen po neat 15 gallons of water at 55 B. contained in a copper cylinder of mass 40 lb. (5.1. 0.1). what resistance must the immersion bester element have in order to raise the tem perature of the water to. 190°F; in 3 hours, aguuming that 1/3rd of the heat is lost” (1 1b,#454 gm., and dək 12 Joules/an., 1 gallon of water weighs 10 lb.) If the heater is in constant use for a 16-hour day, what is the) cost to the consumer at 12 cents per kilowatt-qur? What is the current rating of the heater?
2. (a) With the aid of labelled diagrams explain the action
of a simple A.C. dynamo.
(b) Compare A,C, and D.C. electricity.
(c) à 240-volt a,c, dynamo Is used to operate au 6-voit] lamp by means of a transformer whose primary coil has 900 turns.
(1) Make a circuit diagram 01 Lné transtormer pres perly connected to the source and the lamp. 等她 dicating the number of turns on the secondary coil of the transformer.
(ii) The current in the lamp 18 1.5 amp, * 1f the
transformer has an efficiency of SU*, what is thel wattage in the primary circuit?
FUSE
(2x
48.4 100-48.45
88 ohms
Ir the resistances were interchanged, the null point will be found at the 51.6 cm. mars.
245
iss of silver depositede
of coulombe passed-
current
the ammeter regize:
that is the error of miter
0.001118 gm./coul.]
8.2 8
8.2/0.001118
5600 0.
8,2/(0,001118 x-3600) kap;
2:037 amp
2
amp,
2,037 - 2
0:037 ampere,
Ans, the ammeter reade 0.037 amp. Less
玫瑰崗學校
(幼稚園下午班)招生簡章
班級及人數:
幼稚闖裡菸班共三百六十名! 二、幼鴨類高級班共一百八十名
上課時間:每週由星期一起至星期五由下午二時至五時上類。
星期六期隔選上午由九時至十二時上课•
假名日期:一九六五年五月十日下午二時至五時 •
年齡限制:
幼稚團紀班以本年九月朱滿六歲德足四歲者
年九月未補七歲而足五歲者,
【報名者須據帶出生紙及有關證明文件運團 照片兩張,線名費兩元
報名之日本校將不減校車接強,唐一律搭
66A6Bv11及15巴士。
三、上列各生將不得上升本校小學。
The diagram shows thres lamp X, Y and Z ammeter A reade 15 aup, and lampe Y and Z are ratað at 60 watts,
(1) What current flows through A, 7.
(it) What is the combined resistance of lamps 1 and 27
ii) What is the vattage of lamp X?
(iv) How much does it cost to operate this circuis
for 100 hours at 28 cents per kilowatt-hour? 1.
(v) The fuse flows out because of a short circuit,
A 25-watt lamp is screwed into the fuse socket in place of the fuse, If switches for X,Y and are opened, w£ll the 25÷vatt. lamp light? Why?
有花否守的,生中 考考期之試各及,今在暴長司計 生試者露有攜點環必天
,有主各官把七
科師位試即紫須考釷升摔學,成定核至我崧官立雅,只生
咨示的我
行舉日今試中升 出刋明案答題試
感觀試考付應談界育教 牛時時考验下
母女
字赠于3
自張識對往不,
的、英分五。
赴可招論小大分
惜字字,寫有但試
四咯牛試 降。交五時依
下午二時至二
時四十分休息,
嶺南同學會英文小學招生(上午班)
斑報:
1班
P2P6各級新生
報名:即日開
.
第一次:五月十五日下午二時, 考試:
三千篇天煮十
英间
五樓時
年度升中入學考態度去應付,較注意。
五四三
「愛芝加高雅學校
九龍信義中學招生
中
三、報名自即日起至攷試前一日止 四、攷試日期:五月廿九日(羞期六)上午八時半 址:九龍窩打老道五十二號本校 二、及試科目:國文、英文、數學(插班生加攷史、地、理、化 都:英,F.1新生及F.2%F3挿班生 二年級新生及二、三年級押班生
報報 報 班 水界
名名 名
校放報 班
級:中學二年級八十名 二、報名日期:五月二十日下午二時至五時 上午九畴至十二時
標喇沙英文中學招生
校明
注意:新界學生,僅先錄取
三、報名地點:九靠界限街喇沙書院 交報名費一元。 慶、報名手癀挑C成穎表、出世难明書及最近半身( 二吋)照片二張鴻到校務處報名 並繳
生招
CHURCHILL
COLLEGE
邱吉爾書院通告
以教育的立場,自建新型校舍,創辦本港唯一最嚴格最時代的英文中學 本校籌備務年,由廳議先生落鸦先生軟容醫先生李耀培先生郭若襄先生互相合作,工程加速,本年七月工程全部成,九月五日開學 本校校舍全座苦型,設備時代化,並應聘本地,海老師任教,同心協力創辦本港唯一鋟嚴格長高貴,而使家長長放心的英文雍院,由產率會賬: 藉蛟際學者朱伯奇博士常校長,現公開緩將優良教師,並定本月十日至本月廿五日(招收英文中學1800人英文小學 270人)申情入畢表格時間, 媽所的行截止,仰名家長同學留意然。
小微聘老師:
1.國外學士嶺土博士學位者..
(二)申請入泰日期:
港大學香港中文 台大師大成功大學串筛者 ** 3.本港防癡四年奉繻具有教革輕者
4.相片二照報名費二元,
1.由五月十日起茔五月廿五日止 2.兼帶出世紙及團校迷件。 三)本校概礙:
3.有本羊座升學試證件苑考入學PL
1.本校宗旨:確實,智臂,陳育,平均談,中文英文數細間標並當,變成全體學生有線勝产品性良好之學問及健全之體格
2.本校校舍:本校保自建新型校會,位於九龍油晚地南京衝,踞中帶靜,交通方便,各路巴士為經過本校,繼覺銠良,樓高八屉,內有課室二 十四豔,另為化學宝,物理學,生物蜜,自然地領,音樂發,圖書室、圖書室,電影蜜,各樣特腿堂,另有较務處,校舍案,校駕 話,費事長案等。 言,致學科學化:本校聘有國際地位學者朱伯夯博迁筒校長並麖聘本港官校一流中文英文數翔老師為本校主要科老師其餘一律聘國內外大學土 及有濕地教网溜在上課時除老師發解外差粿鯻帅備錄音一架收錄主要跟理以備學生將餘複習再戰電影国放影蝻助歌背影片各科地有實魏国 地頊您由專家設計特業電動地圖以利學生記镶常本一特別繇宝 •
6.管諷賤格化:
上課時間:藉對還守馆制到早退上課時間校務镔學生自由出人踝足絕能止咳率並生成自勦軍領落日規定當作四料
校址·九龍油蔴地南京街30~36號
邱吉爾書院 監督:郭若蘭
電話:854898
董事長:李培
第二大:六月十九日下午二時
九龍石硖尾白田街近2E巴士站: 校址:
2D,6A,6C6D等到巴士司簉
(下午津貼部及夜校同時招生。電話八六八三一三)
午进口術
【利瑪竇神父書院
招收1965 -66年度新生通告
敬:由本年秋季起• 本校中學分男女生
部,女生部,另彀小學部 名稱及 班級分列如下:
(一)利瑪寶英文春院男生部:
F1F.2F.3F4F,5(會考班),F.6
(大學预科班)
(二)利瑪寶英文書院女生部:
F.1 F.2 F.3F.4 F.5(會考班) F.6
(大學预科班)
(三)利瑪費英文樂院小學部:
P.1 P.2 p.3 p.4 P.5 P.6
明及
班及答案,均 於明日在本報
在會所舉行照光找著做,別真格·李
大主纛 領島學校招生
(萄树 本·康採取沉樸冷靜的分出,請讀者
二十六年段六月十六日下午一時
各
午一時十五分在代郵:成君 中華補影師會
華
法相高明,有5
竹熱
翁!散排名变五落,他敬軒名家!
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