1967-02-16 — Page 20

四第五第

八初月芒年来丁启言

英文中學會考試題預習 專欄士

$2.

沁沁年

物理科

育敎僑華

(十六)

·梁海明·

PHYSICS. (16), HI.M.Laing)

Solution.

中文中學會考試題預習專欄

29.(a);

物理科 (十六)

鄧炳恩、

EYE LENS

OBJECT LENS

/*ne object is placed a little farther outside the focus of the objective 'which is a convex lens. The intermediate images.Iy is foimad a little inside the focus of the eyepiece, so... that the final image I seen by the eye is vir tual away ffom the lens.. Microscope objectives have focal lengths ranging from 1 in. to 1/12 in. and eyepieces magnifying powers from x5 to xl2. Hence the focal length of the objective^ is much shorter than that of the eyepiece.

和功填-

題及問答計算題題解 填-

題~

一可作功、2142.854元不

13 W = 5000 × 4.2321000729

72*21000 +9.8=2142.85盘仟元天

2铅弹速度為162/秒

解:設铅弹之速度!

則士x220V = 4.2x10*x20x0.0315x100.

V = 16200162

公年六十五國庆理中

w為引擎一分鐘所作之功 鐘所生之熱

為引擎

QB 分鐘捐一头之一热一重

w=1800×60=108000焦耳

108.000

10. =( ~ 1 = 1 100 000 = 725.71.4.3.f

A

4.2

18000 × 0.09×11+5000 × 1 × =5720f

QIQ-Q=2571437-157 20

1=19994.3f÷120000 ₤

鞋頭要哭我体滑了時所受之摩擦力

為物体滑厦30吠所生之熱量

則f = M200.05sbo_= 0.25 x_100

|= 25 磅會

گھر

w = f-s = 25 ×30=750呎磅重

i

Q = ~ = 750 = 0.961, B.T. U.

4

解!設物升走高温度則

780

[ in = 4 em.

mx 0.0 3 3 x =* MX 980 × 1000

£ = 0.71°C

四、聲學

12 x 107

Magnification of the objective by measurement

> -5.

4.庄える熱

489x1

聲波和聲速填-

題反問答計算題 填-

題

P

1 聲波順風時多向

折射;逆風

折射 又夜間 折射白畫反之

波多向氣溫較

之處折射所鞍

I in = 8 cm.

Magnification of the eyepiece by 'measurement is m 6.

(.". Total magnification -(-5)(+6)

(c) f=50 ft.

u-240,000c5280 *

wi+Bran themformula

=-30.

57 x 1000 x 3600

2 x

20.52 x 10

(Q =)

4.89x

5. *

解

至少在自34286 米

冰塊自克厘米落下則

2.人所能聽到之聲頭要為自

mx 980x h

30 # 1 20000次,若臂速為340 則最低音之波養為

最高

4.2 × 107

波長為

丸 = 3428600 厘米=34286米

峭壁相距:1020米

嗎

較

合設峭壁折友之间 第三峭壁折反者早2秒鐘 蟹速為340多秒則此人与

峭壁間之距离為

”

30. (a)

u

4800x5280′′

. Diameter of the moon

4800x5280x5

12x5280

2000 miles.

Answer: The moon's diameter is 2000 miles

sunlight

approximately.

Violet

Holt in

Lindigo.

shutter

Prism :

Branged

u

50

240,000x5280

安

Tagnification

临

4800x5280 - 1

240,000x5280

1

倭器長約1米两端有不塞之硬咭 紙 圆筒餐粒 温度計 米尺天 秤

鉛粒重為

吳振 方向成

动之方向与波傳播之

行者稱為

过而不相等之两波

同间

CON

最後铅粒之温度為大 量硬

量最初鉛粒之一温度為大°C

傳播時

丙

之聲音稱為

紙圆筒之長為(如图)大程

3.- 8 x

义之频率为1024次/秒,其波長 連:32種,則声速為

温為

Ch

J = r n mgh

ngh

White

Scritt

sltrat

問答計算題

7.試述一驗証明聲波須藉介

後一傳播,

12.何謂『共鳴試还 驗明

small

/Light from the sun streamed through hole and passing through a triangular glass prism. An elongated coloured patch of light was formed on the white screen. The colkurs are in the order Red, Orange, Yellow, Greeny Blue, Indigo and Violet. This band of colours is called a spectrum,

Diagram of. apparatus to forma pure spectrum) is shown in part (b)

| If a piece of yellow glass is placed in path. of the light, only. red, green, and, yellow can) be seen on the screen. Because, the yellow.• filter absorbs blue and any colour consisting blue. If a piece off blue glass is placed in: the path of the light, only blue can be seen, on the screen. If both sheets of yellow and blue glass are placed in path of the light, nothing can be seen on the screen. (b) The pure spectrum is that there is not any overlapping between two consecutive colours in the spectram, That is, the boundary ben tween two colours, is distinctly clear. The impure spectrum is that it consists of a series of circular coloured images all overlapping.

White Light Source

Prism

Lens to focus

•Light on stit

Spectrum. Formed

A ̈ converging lēns L is placed so as to form an image I of a narrow slit S brightly illu- minated by white light. A prism is then placem in the path of the light from the lens, Dis- persion of the light on passing through the prism leads to the formation of a spectrum VP on a white screen. This consists of a series of coloured images of the slit all touching, orie another

The colours or the spectrum may be recomm bined to form white light by allowing the spec- trum to be formed on a row of small rectangu- lar plane mirrors. On adjusting the angle which the mirrors make with the incident light so that they all reflect the light to the same place on the screen a white patch_of_light is formad

Topica Tor revision this week:

1. Mixture of coloured lights, Coloure by adsorption. 2. Simple ideas, of photometry. Inverse square law."

Shadow photometer, grease-spot photometer.

Questions.!

(j1.(a) A plant with green leaves and red flowers in

placed in: (i) green,(li)red; (iii)blue light, What colour will the leaves and flowers appear in each case? Assume all the colours are pure. (b)

A lamp illuminates a soraan si e perpendiou.

lar distance of 15 ft.To what distance mat the lamp be moved to double the Illumination of the screen? «

(c) A small 50 o-p. lamp is surrounded by a globa

which outs off.30 per cent :of the light falling.. on it. What is the intensity of illumination: received by a book on which the light falls normally at a distance of, 4 ft. from the lampy, (32.(a) Describe some form of photometer and explain

how you would use it to compare the candle- powera of two electrio lamps.

(b) In an experiment to compare the candle-power,

jof two lamps by a photometer, the following

series of readings were obtained for the dis-1 tances of each lamp from the screen: Distance of lamp A(cm) 10 20 30:40.50.60 Wistarice of lamp B(om) 11 25 35 49 62 70 Flot these results on a suitable graph and hence determine an experimental value for the ratio of the candle-power of lamp A to that of laup B.

(o) A lamp 3 rt. above a desk 18 replaced by

canother of.55 pen cent greater candlempowerJ At what height should this be placed. to. givd Che same illumination_at a point directly. beneath it?.

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