質二第張四第 日七十月正年西白麻里 WAH KIU YAT PO
報日僑華
三期星日五月三年九六九一屦公年八十五國民藐中育教備華
CC文中學會考試題預習
1969
物理科 (十八)
隆永熾
PHYSICS (18)
(a)
The 'incident ray AO, mssing through the Optical centre, will not be refracted. It in a straight line,
eeds
The incident ray CD will be refracted and cut The principal axis at a point inside the foca
The incident ray must he parallel to the principal axis in order to be refracted through the foes
The incident ray PQ, which is parallel to the principal axis, will be as through the ray radiated refracted from the principal focus
haya through the optical centre which are undeviated. Therefore, the incident ray at 0 is aimply KO. produced.
The incident ray at X is a ray parallel to the principal axis.y
(b)
kays incident normally at the mirror will ba refracted back through the lens and brought to focus in the same plane and at the saxe point, ás the object. The distance. between lens and screen: O and now gives the focal length of the Jans..
The principal focus of a convex Lena, or a. concave Lens, is that point on the principal axis to which all rays parallel and close to the axis converge, or from which they diverge. after passing through the lens.
By Lens Equation
with "ral-19-005171ve convention focal length of concave lens
11.
distance of virt
一種已位無方物
The object m the
ced 24 in, from
主蚘背政府
(34,7(a) (1)
radial muscles'
of ciliary body:
cornea,
queous humous
circular muscles
of ciliary body.
humous.
Main feature of the eve
choraid
yellow spot
{fovea
(ii). The ability of the eye to focus objects at
various distances is called accommodation and is affected by the ciliary muscles.
The minimum distance from the eye for an object to be observed with greatest detail and without atrain is known as the least distance of distinct vision.
The advantage of. possessing two eyes Mamma Is see with both eyes
Simultaneously, This provides the
binocular vision, fecilating them to have the depth of_objects.
(6)ähort sight of myopia is a defect of an eye ini
accommodation. The image of a near object is able to fall on the retina while the ciliary muscles fails to focus. the image of a distant. object on the retina even though greatest. atrain is made
Short sight is concerned as either the 1 eye ball is too short or the over-fatigue of ciliary muscles so that they do not relax sufficient to accommodate distant cbjecta.
Prism binoculars are used, since it gives erect images and has high magnifying power.
(ii) A galileo's telescope or opera glass givesi
an erect virtual mgnified image. It is lighter and more compact. (ii) A: magnifying glass is used to examine a tiny insect. To scrutinize each part ir detail a compound microscope is used..
To produceva pure spectrum co a screen, the light source is placed in front of a narrow elit; a wide slit would tend to produce and overjapping images. A convex Lens in front of the slit produces a beam of parallel light; the distance from the slit to the lens is hence: equal to its focal length. A priam will disperse the light incident on it. If the source: is white, the emerging rays have colours of red, orange; yellow, green, blue, indigo. and violet The rsys of each colour are separated. A coivex lens collects each or the coloured beams. Each colour is brfought to a different place or focus because each parallel: coloured beam travels in a different speed
A red flag, when viewed in blue light, appears black, fure blue light does not consist of red component. The red flag absorbs blue and reflects nothing
when it is viewed in red light, the flag, appears red as it reflects red light that incident:
A red, white and blue flag appears black, and blue in pure blue light. The red portior absorbs blue and reflects nothing, so it appears black, the white and blue portions reflect blue light. In red light, however, the red and white portions reflect red rays; and the blue portion absorbs red rays and reflect nothing as the incident light consts of red component (only. The flay, in the casey appears. red and black.
Questions for next week
35. (a) What is meant by the illumination (or)
interisity of illumination) of a surface? Name two different units of illumination, and explain their meaning.
(b) What is the inverse-square law of illumination?
Describe how you would verify it..
(c) Two:Lamps, each of 200 cannela, are placed
together 10 ft. above the centre of a table- tennis surface. Calculate the illumination at the centre. In one lamp breaks and is replaced. by ariotner of 160 ck, at what distance above the centre, must the new lamp be placed to provide the same illumination as before.
.d street lamp of 100 c.p. is placed at a
height of 20 feet, above the road. A plane
教
育
書號昨發出聯合公報
界之意見通告相 對工作待遇方面: 學生與工業
• 賨年類袖訓獠棖所有工作,均外 本人之努力,及其周件之協助,迎刃而解,共
「本港工業與大學生」研討會
敎育承院寻事行, 下完并论,假羅富國
明日畢業禮
港區師班 | “是於明日(星期四) 一例六八年級畢業典 帕朗、香蕉花師
本港第一間青年領袖訓練學校
有
目
今冬在港開設
用的
經
民在立
星助託
最
人
會
近
發
貨
關
造項
力
有用公民 星加坡最近已設有一間 目的 在協助青年人發展其才智及創造力成爲社會 官立業影學校, 經成立信託委員會負責有關籌備事項 此類學校之一 ,各生對
Hy凿墅出髙家,正孫險家,其忘惴其能絳察窩 。各校之所以检出此璀潑境,非欲仁運生成绵海 勃,從而设瓤並如把人類,可降阻之体大新升
嘉兴護守嚷付 顬俗,其景德宫貼可钻,而交往
湖神之君,在灣發做人之振作精細與努力,聯合主然之「本市工,作花 學生會與浩大工邑基會設立工業指議委舟,
。是院假攻大會堂雅行,努力相比校,供其前此仍達佩寫之宋之,八日三月7日 一週 學位課程,助其設立工CE) 天假香港大學娄行。 助理教育司何雅明指出
嘴究再作比鱙。∵
研討會於昨日出
姚統,其目的在迅速巡查其自信小及體力,但其一也
住
社會人士甚爲讚許,
正踰
各維訓線之設德。 樂指導委員會,並推出 漢,如两科併排一日,一,六年制
們對於工作時間, 「憲尾,各有不同,學生」一時始能完畢後,有點主餐。. 凖生與工業界两方面的,使兒童在晚間預左, 鞫,因爲影响露小之收
· 在工作待遇方面1 練習,功課之盤案,有一萬,頗能獲得家長之信
一
菜界創客爲該字塔 為渥利有所不滿,而工師均能,何氏之指示
混進而論,現年之工作,於智為教育,教我,向日就善成立「潮」 政府發育家官小月3日行選
教你有旨,希望一般酸 珠海書院同學:
·散文 研究社.
次,請片的官小一年艘」,財政布说議。 一所學校多中小一郎接泱泱炮,關琺福,生動
形
學生具有此橋紀難時,即行難逢其主級換器,
助理,光海;在校帕倒數由裡斯小麥提高建民,高院明在要被·雷 就該務機構去說,就形成的高,東盟此者,常駐研發熱,麥曦際
板分開家須小心評 至於航海鮮,公開後,它山若路及在無人地,設立必修之桑難實習會,勿望隨封專學生休的各年級,形成爲 港府教育工作人員 支持 之指摸,此點特別著 管司何何培育前在流主席提出討論,故小學州曾自幼在西到部貼有臺海係,風間一 【然、凤村宁中航一紅一切有忠的同梨品加
然葚前斯未有此稀洲無者。
成立信无天天本雲實有跳椒架事項。 !(PC)本港第一閏青年發袖訓姊學校,預。其辦法戶以受盡之青年,置於人覑生燕直灣長 各风流,他隻會發現其自己之所畏,鬧「警找方向之方法,
第一,地殼工業管理的科目
【固有之不傾,使其對所經瀕之境過,不同之一
|期在本年十月、十一月之間,在香港成立,經已害寳門之環境中,他其自也累,分期其水菠尹隊,染色长明,程-增加校外祺程和閒時間,主張家鴨式教育,以幼小之一
「精神,冷情現家活穰片,均可干以 花 。 上部總質袖慧牧之主張,架已風行各地,今日,感。由此對於近代社會上之一可陧個,缺工冒險,來畫所爾窟業,必須盡之力,以表各功 學生流向及進計精神,爲奇抽
生將有機會接受所獲其領導才能之門棟, ,對半張蘭訓練學校之運程,包标有服務社會
大心中大以及工冰的恶 一學位。套泛來說,在港 學科追得上時代的宋减少,求亲誤不夜
中能,食因過宙之功,
貝納祺胡鴻烈陳子鈞競選
平時爲多,彤星期有
花在之若
,爲欣東効力,故在燕芬學生,在校內梅舉此一
,來解决工業人材之
一。瓿爲發會人士,尤浦
| 在情况下排良心,将立見其之熊與本,有米宁備,由學校廣生担任其事,對於救援工生眼光短浅及過份
光有
「
,對於各科著作,若非
,「中文宇宇一種鬱,他有之,該會之法律殿門優名衡問
• 往英投濉副會牙,中文一 受以神之一。 「法平生家長所讚許, 每日不應超過十行,因多年,對誠軒會務之推湖,具有一定之感。上 目前有所體國語,生字,經各學校會民盡力支持,並於一肖
六年, 熱心服務社會之何名人士,影的奔 誠有損於小學生之心
八、香港政府秘育工作人口湯之年,
一
摩
mirror of reflection factor 0.8 is placed
feet above the lamp. What is the illweination
of the road vertically below the Jamp?
36. La/hhat is meant by the wave length and frequency
to
of a sound wave. Explain how they are related
(b) the velocity of the wave.
Is the speed of sound the same at the top » of a cliff as at the bottom?
(ii) If the ain in a rcon warms up, does the
Speed of sound in it increase, decrease, or remain the same?
Baltec L
(c) Doês the pitch of a note heard from a radio receiver alter if (i) the volume control ds turned to make it louder; (ii) the room becomes warmer; (iii) the tone control is varied? Give reasons for your angwers.
lower
(d) The velocity of sound in air is 340 metres per J
sec. what is the wavelength of a note: (i) one octave higher; (ii) une octave lo tnan the note of frequency 680c/s?.. (e) a man standing between two parallel cliffa
fires a rifle. He hears one echo after 1 sec. one after 24 sec., and one after 4 sec, explain how these echoes reach him, and calcula te the distance apart of the two cliffs. The velocity of sound under the given conditions 19 1120 ft. per sec.