貝三第張六第
日五初月二年宋丁廢友
英文中學會考試題預習專欄
-
物理科
(二十)
·梁海明。
Physios (20) A.W.Leung
15 MAR 1947
WAH KIU YAT PO
Proauce Nx"to anypoint"P.
Then the field at X due to xne magnet de the resultant of e field m/250 gauss alone XP and a field m/250 gauss along XS.
2m 02
HALL
Hence the resultant rield = 2-Cos 1 kauas . in the direction XR, which is parallelito NS. where A. ZRXS; LRXPI-LCNY
ON
5
respitent field£at.&.due to the Inaane v
yolution.
37.(&) Let AB represent the magnet and I the
position of the north nole of strength 60 unite.
sinoe the wagnetic moment (附)
pole strengthín) r distance between the
then
色 -
160 - 1.10
36
poles.
unita,
Strength of pola placed at X = 60 units, Distance of the pole B of magnet from I - 10
Distance of the pole A of magnet from X - 20 am 、
2m
一
Causalong,
Since 'X.19 a neutralipoint Ether
2m 23010
---0715
0.18 -12 wǒ units or poiemetrengn- .". magnatin moment{k} -0.18x10x125m
Answer
Applying the formulė Pe →→
to the nole
38. (a)
B and the pole at A
36 x 60
F1- 2
101
21-
F
10
A
aymee.
Applying the formula, Fo
A and the pole at X.
2
36 x 60
20
dynes.
to the
pole
The resultant force on the pole at X will be the difference between E. and F poles at A and B are unlike boles.
F
- 16-2-
1
for
2
dynes
dynes:
Answer: The force exerted by the magnet
on a poke of strength 60 unita
is 16
dynes.
(b) "Line of magnetic forcer: To explain thia
we have to imagine something which can never exist- a single north pole. If we place such a thing near the north pole of a bar magnet. It would then move around in a curve until it reached a point: near the
eouth pole of the magnet. The force of r- pulalon from the north. pole of the magnet
from the south-
and the force of attract1Cause
pole of the magnet would cause it to travelo thie ourved path. We can now define the term line. of force as followes
The line of force of a magnetio field. the line along which a single north pole. free to move, "would travel if placed in the Tield. The direction of the field at any point: islgiven by the direction of the line at that point and is the direction of the force exerted upon the single north pole at that polat -
712
unite.
unita. The magnetic moment of the bar-magnét 18 712 units.
Portn
Ir ve plage an zron" par "against the north polé of a "éagnet and test the far and with a compass noddio. The far end will be a pole. If the iron bar is placed against the south pole of the magnet the far end will be e south pole. By dease of magnetic inductidua the magnet turns the phece of 100 into a temporary magnet. For example, we can hang a number of small naile in a chain from the poles of a magnet. If we remove the top nail from the okain, the whole ohain will collapsa end the naile no longer cling together, The magnetism induged in the nails hanging from the north pole of the magnet must be such that the head of each nail must be a south pole and the point of
ach nail a north pole. (b) The magnetio meridian at any place is the
Bisection--in whion
ra good compage needle Boints at that plane when it is acted upon Bolely by the magnetic field of the earth. The angle of dip re defined as the angle between the total intensity of the eartha hagnetic field and the horizontal.
Magnetio declination:
『The angle between the
magnetic and geographic meride ans is called the magnetio declination.
To determine the magnet10 declination at a given place, we have to find
out the geographic meridean
as well a the magnetic meridian.
A sheet of paper is placed on a vapie which nas been levelled and placed in a position from: which the aum 28. vieible at midday, Pima are fixed to 6, s čude of a bar magnet which issuspended just above the paper by a length: of unapun silk, When the magnet has come to rest, points A and B are marked on the paper immediately beneath the ends of the pina. The magnet is turned over and new positions A and B are marked.
A
Fig
在香港大會堂。
“支成材
因滿
此
的道
校際小學土風舞比賽
决賽順利完成
·期軍初,興資服
←玷小冠妙比热賞塞
一般而散。 體育視 學營精憚,預袞汜念堂唱全盡 大會問筑楊夫人以國語演說,由新界 |級政育宫金波蜜致詞,對諸生她有。 ,循循善。 畢,先酹教育司界育高 【夜各校數師園東方土風舞之研究祺有心得 學校。西方士風無多穿校服演出,不另置。( 一而監灾。總觀全部突程,各生之宾現,足和縣學校,元朗風光準校,聖母無玷裾,一座乎無玷靼心小學,正耳救世軍光著小學,非決定組織,但其就來,而是在數年之後獨批炸出門, 一民刊古代形格,音樂修櫌悅耳,舞宓妙美文基公立學校,撰洲公立瞑,河溪學校,一直光智小酷,季正元起黄光,高級組冠軍,因被台雅路一邊短期內可以鐵到的小四日。海外熱感服 午校,舞名萬告顯腾,化裝類如新驳西藏·學校,荃灣全完第一校,荃樣信夔學校,初級証冠軍跟母無法做心小學,並軍救北極工的開心著的委員 之寶用人材,恐怕不歐明 徵,以最幼小之一女生穿禭形驗,發出行,是日參加之小學高級組有荃灣何直,每當小學生數形散熱時,搖就頓足,有一項全面的工蜂辦 太湖 中有可望蓽喘,萬業師 一級還之狀,風格獨到。不寧大沆眾官立上,聖母無玷积心學校。初級組有救世算光吧一直如愛,因為天。比果,小路旁工訓練之股,做,若要-
份體得各級 張士女校,今年的, 踱手,個人演出茜佳,其餘數名舞員,作學校,救世軍光智學校,抚州公立學校, 其競盎然。男卿籲志發沉中橡鑿,另底線針對訂定。度一切的別練再宣院,當賴寬院 伊之獨河工夫。亞軍漢語附小,對名拔顯 力 土風舞比賽之期,铁亞灣官立中學畫 服酸,其音樂與卿蹈和爾。三位外潼女評書,而現止,仍題,先要解决所有蓋 浸會杳院,香珠工業 本凿工業激育及。因此,本港工商界,金文泰中學,運
工業教育雖重要
發展上仍嫌緩慢
實係在摸忑現溯神。
一璿論。報告書籍、解 侯 許多有關的 供委員會研究所得之參加留美考試學·生
參茲本問題」。阿基 前,必須先行解决許 顯示碰到許多困難間的熱點。 (南) 质施一項眺規計劃之該會報告塔之過囂,,才熊照付接鬬而來 一項報告,謂一本, 藝術軎官。但由於 努力,服許多困難 在去月底向政府提出刻,質前本港各項工乏下,太確仍須舉 感到失望。該委台會的段施丽作出全體計 在面臨辦人材:試報告表格设
日五十月三年七六九一年六十五國民奉中
乎被斯頓,明 能錯過期,熱影
報名日期,否 多黑三元,可
及三月二十日止
在三月十日用
一促請湯生注意,或
最遲本月十五日
商會小學(痿痹菜,新蒲崗官,竹舞 料蛉由凌道夫人,王小女士,娃 雖一心,激臙門基衆袪闖),基愛小學(山地竹牛攝),救世軍光智,偏愛正必小 地竹牛簿),戒光小學(太平,開本 〔花瓣),黃鶯和張小學「要山), 官立中學禮堂舉行,參加之學校有大抗東 桑布攝),聖墨小學(沐花無〕,大埔魚 九及新界小學東方風舞此案,巴富術(小艾),附小八格巴 庫爾。 校(舞),巴巴(舞)钟上一幅各生無染,鯨聆音樂,當彌爾曲終* 朗律而整齊,笑容由內心而外狹,此 官立 〔萬景緻疆),望M小學一盥飛舞民小學六阿里山小姑娘),大地東亞(山-鎮漢華附小,季軍大批取官立上午校。 u,孔融三槃(蒙古快于瓣J-峦神下午琼女士,黃馬沙爾女士担任。四位正 中國古代宮女服裝,爭持館巾,舞姿 比心思,冠軍鐘重緒幹就裝學。跟 秦小烈士萬要比賽,邬八十三)日,爲花旗黙小學〔形巾鋼),創葜附小(竹竿|下游出精巧之舞爽,使患者笑謬蕭驗,蒙 冠軍之舞名爲彩巾斜,學生八名,來
「特杌♪呑把承界琦育協鸿會主辦校 中棁( 鴨子軒),瓷器附小(切羅说),一細心醉值,热段京应议。各生在依据沙曲 一是日塔决貿性質,挺品留特三十一
· 需要許調各方面的大事。
有烤內而形器外。 獲得身心依快而后已。(琳)
刻,亦心神策,是卽心於舞照,
之長久計劃。該商根 ,時音樂响而神愉流露,音祟响時,安起學生的增加,以及較量。裘樸詩現時的對,但因計劃寵大, 不 慰自馁,须接再厲,力求進取,灣使。面臨於工界,材展。
支配,神態檢悅,亦足以表示舞蹈之内容 【以音樂配合舞蹈,表情與舞,由音樂 | 舞,必先飛當地風土人來與習俗,然後 成地方之土风人情形特性。善入學習士風 | 晳之一,以風土攝笆之,乃表現每一碗的 安夫人襬照如下:舞蹈門攝 曾誇歉,心的完全橘無脂內容術治,出標一支現在工被學校及工高,才能與其他各國有國進行全面的計畫的分工供商之所必點 本規定由小车接起間如於大之大學,亦指重民生如何證付業 燭難,貴精不貴多,更不應過於重複,解取得進一步成親,此產品質量及效點上絕的重要性,因而奏在來有-
足的經過問辦 則缺乏興趣,太深則始於形容。至於安科有關人士努力下,旦競爭的精戰,须要在上都瞭解到一因無 苴關切湖開保本港將 日
或是高級的人材,來的朗熊神陸對要性 面推進工作為由。休斯經狄育考試接带,遭沒考式每年土法體會對議,可到九 ,今日各校演出之糖巧,航令幷科負雄致育有所發展,但在
。資料之選擇,應適合兒意之程度,過換
本港面臨管國際市區 香港政府及工要界人 在在的短期制題,而 工業體育,在當局及 於下第,然而中握著幸勿自豪,而洛築者· 速度而言,仍嫌般步支持本港工商業的泉會,到目前儘止,尙書報告呂雅宋證明,在辦之標準英文考試 月,一月及四月在香
進顯示有待克服之困難尙多 工業教育諮詢委員會不主張急 [鸱杌]香港之合社會之開。同時,實在佔主要的地位,但骸食不獨照及必然 劃。昔日租逖子夜闖鈎潔,就幫現北起舞,青年攻煞此方面料市場及權大發展,就故底資尙米拉楣意地付了脫北金捽後來,,香熱學生赴美升學到熱採取熱式,作為構,假意好學生黑 雖然,本港工無材,無論低級、中級一九六五年成立解密及一般雄成之友 碗院,均與要通過資程度。 量,未有突出的工作表藝研究及醯現之有HOEEL,才能獲 洪分九個越過舉行,底分為與及報名,
|題的進展似乎规吗? 母实按步就班,依照,不擔鈾燕大學或所醉定外國學生之英交 求,我特增產期一、 四月四日今屆最後試期 被老台過去數年展 三五騰新班,名參
應寄報告表往美
|龍參加TOEFL
,能順瓢望過,轉
一
十一日頒獎 方土風舞組冠軍聖母無玷聖心小學 定三 東方土風舞組冠軍鐘聲慈善社義學 西
來殺
宋脅的—步故凱道的十
日日熊九尙因進性解,
【昨六十四日爲校際小學西·鲜方面给售部經許多,方可 推簽發老美學生入境包括在崇學院,地八八二八十七。
但證,此外,有一千一港大學,聯合世院,一
緻年
Fig.
"Positive direction of a line of magnetic force is the direction of the force exerted upon the single north pole at that point. All. lines of force have the same direction. This riesc iná 18 away from the north pole and to- wards the eouth: pole
(c) Je shown in the diagram, since x 18 A
neutral nötñt it follows that:
Field At X due to the magnet d Field at X due
to the earth,
Letim unita the pole strength of the magnet.
femag.)
ABR
Join AB and A'B'. The direction or the mag- dotic axis and hence, the magnetic meridian. la the bisector MM' of angle AOA
Next we locate the geographical meridaan. A plumbline consisting of a length of cotton with a weight attached 1, hung from a stand so that ita shadow falls on the paper. Exaotr ly at noon, the position of the shadow of the cdtton is marked on the paper. The angle be- tween the geographical meridian and the mago netic meridian is the magnetic declination at that place.
(o) We can use a soft-iron ring to shield the magnetic field of the earth. We put the small compass needle inside the ring. The lines of force converge upon the ring, pass through the material of the ring, and emer- ge from the other side. The space inside the ring je.left free from lines of force.
Field at X due to N pole of magnet-·
in direction, NA,
Field at X due to SooleŻDI¡ magnet ri
in direction XS.
(gausa,
(NX)
m
gauss
These two fields are equal in magnitude but are hot in the same straight line and have to ba bompounded.
Let C be the mid-point or N3,3then in rtANGX
- 230
NX -√250 - 5,10
aleo NX, SXT
N
Topics ror revision this week::
S
1. Simple phenomens of electrostatics, conductors
and insulatora: charging by induction.
2. Primary cells and their defects,
3. Accumulators lead or iron type.
Questionë.
39.(a): Given-a gold-leat electroscope, ancedonite
rod and fur, explain how you would use thems (i) to detect theipresence of electrostabio chargehen another, body:(11) tò find the sign. of that charge.
dive e labelled diagram of a gold-lear electroscope. Explain how you would(1) charge it by induction;(ii) use it to show that the charge on a hollow conductor is situated
(c)
Describe an
an electrophorus.
An insulated baass ephere me given a positive
charge from an electrophorus. What happens if it is then brought into contact with (1) the outside, (ii) the inside. of an insulated hollow conductor?
40.[a] What are the essential parte or a primary cell? Explain what is meant by polarisation and local action and describe how theae are: reduced in the Daniell and Leolanche' aells,
(b)(1) An electrio motor requires a supply of
6 amp. at 12 volts and you are given a number of lead-acid cells each capable or supplying a maximum current of 2 amp. Show in a circuit diagram, how many cells would be required and how they should be connected
make a battery capable of supolting the motor.
(11) Byre-grouping, could the battery obtained in (1) supply motors requiring! (1) 36 volts at 2 ampa(2) 18 volts at 4 amp In each case indicate the new grouping and connections of the cells.
(6) Nans two advantages whion a lead accumula-
tör has over a Leclanchet
END