position, he would not have said such a thing to that poor girl.
Articles:
ENCE LIBRARY
***
真三第蕓三第
日九初月正年申戊麼复
0968
#
文中學會試뭣預켭卑閬
WAH KIU YAT PO
1958
期
會考試題額習等调
物理科 (十五)
陸永熾。
英文科 「十五)
何玉柱•
Physice (15)}
[Xv
lar nouns are
27. (a) Refractive Index
The ratio of the velocity of light in air to that of a medium is called the refractive index of the medium.
or
The value of the constant sin 1 for a ray]
sin r
passing from air into a particular medium i5] called the refractive index of the medium, (where angles i and r are the angles of incidence and refraction respectively). Critical angle
When light incidents from one medium tr a more optically dense medium at a certain angle of incidence. The angle of refraction is 90°. Such an angle of incidence is known as critical angle.
For angle of incidence greater than the critical angle, all the light is internally reflected. This is known as total internal reflection.
(b) heat depth - reading (1) - reading (3)
(11.95-2.11) cm. Apparent depth - reading (2)
• (9.49-2.11) cm.
Refractive index • real depth
- reading (3)
apparent depth
11.952.11
9.49 - 2.11
9.84
7.38
-
1.333
Ans. The refractive index of water is 1.3
(c) (1) deflected through 90° (11) deflected through
1800
As the white light incidents normally in the prism, rays of different wave-lengths will not be refracted. Consequently no dispersionis noticed after emergency.
28. (a) The sun or reciprocais of the object distance
(u) and image distance (v) is equal to the reciprocal of the focal length of the concave
mirror.
+ 1 ·
14
20 25 30 135 40 45 50
22.5 21.4
u (cm)
v (cm)
60
37.3
y" bulo
5
4
30.1 26.2 24.2
3.33 2.86
2.5 2.22 2
u.
(am-2).
*x10-2
1.672.68 3.32 3.82
4.134.44 | 4.67
*
(cm) |
Answers to revision Exercise
1. 1) had been (till last week)
2) had hoped (also before last week),
3) came (last week)
4) shall have("soon enough" denotes_future)
5) do (habitual 'action)
6) were
7) be (condition contrary to present fact), 8) will love
9) (will) do (promise)
10) grow (in time clause, present tense;
takes the place of future)
11) were (subjunctive after "wish").
c. 1) He will study hard if his father lets
him go up to colege. (Present tense is used in conditional clause.)
P) She works so hard that it is easy for
her to pass any subject with flying colours.
3) In spite of Toni's naughtiness, ne
never got into trouble.
4) He set his alarm clock at so that he could get up an hour earlier. ("Could" is used to show purpose.)
5) I'll take a book with me in case ne is
not at home. ("In case" already suggests possibility; do not use "may".)
61 As soon as they saw a man climbing
that building, they called for help. (? Immediately" is not necessary when we nave "as soon as".)
Lne
71 The more they wanted to get out.
harder they found it to break the lock." 8) No
sooner had Joan reached home than it began to rain. When we use no
at the beginning of sentence, We should put a peculiar vers in front
of the subject. 2. "Juet and "at almost the same time" are omitted.) 9) Whether there were any wild animals in
this forest last year is still a 10) He failed to turn up because he was a
3. 1) "Go home now," said he to his brother.
2) "Is it true that he stole his mother's
ring last night?" I wondered.
-
3) "Oh, what a nice surprise!" cried he. 4) He said to her, "I will remember you to.
my parents when I see
them."
4. 1) He asked her how she could explain t
little children why the earth goes round the sun.
}
+
2) She requested bim to pass ner the salt
and then thanked him..
41 Mar
they were too lazy to
———-3-*-“
By Mrr they would still go fishingafrit rained. 5) His brother said if ne пас Deen in his
We know that 1) is a straight line graph, Is confirms the relation of,
+
1
o is the point where the graph auts the
There are two kinds of article: definite| article (the) and indefinite articles (a, anl.
They are used before nouns.
Indefinite articles are used when singu/
e.3. used in a general sense,
A bay is usually taller than a girl. Here "a boy" and "a girl" do not refer to particular boy and girl, they mean any boy. any girl or ordinary boy ordinary girl.
"a" or "an" may also used with singular nouns to mean "one" when the nouns occur for the first time. erg.
Yesterday I saw a European surroundeo by a crowd of beggars.
"A" or "an" may also mean "each", "every"
e.z.
a
uay.
run 120 miles an hour,
He earns ten dollars
can This car It is not necessary to put articles im mediately before nouns, we may use adjectives-
to qualify the nouns and adverbs to modify the,
No matter adjectives.
what part of speech the word after the article is, there must be a noun. You cannot say: He is a very brave..
very brave: Either say: He is
or: He is a
very brave man
"A" is used when the word immediately after it begins with a consonant sound, that is, the word may begin with a vowel, but if the sound is a consonant sound, "a" is ap- plied. e.ß. a European; a university; union (they all sound like "you" which begins.
(read with a consonant "y"); a one-eyed man as "won"); a rather big ball; a
"An" is used before a word that begins with a Vowel sound
matter the word has BO vowel or a consonant at the beginning. e.g. an honest mani an old lady: an "s":
an
*** etc.
મ
601
eye; an honour.
"1" etc. This point must be noticed as I have
use "a" and found that many students cannot "an" correctly because they just look at the
Do not be words but they do not read them. deceived by appearance.
#
趄
-- Definite article "the" is used with par- ticularized nouns (both singular and plural), What I mean by "particularized" is that the nouns have appeared before or are qualifiea
Read the by adjective clauses or phrases. following passage and see for yourselves why efinite and indefinite articles are used: Once there lived an old fiddler in small forest. The fiddler was very por
&nd e had nothing but a one-eyed cat splendid violin. He loved them both more than himself. One day, the cat, after a nap,
became played around by itself. When it tired of being alone, it happened to see the violin lying on the bed of its master. Feeling curious, it jumped on the shining instrument god began to play on the fiddles, malas pie by one the fiddles were broken; the poor CAL did not know that it had broken its lonely master's heart as well.
---To be continued---
BRARI
ONG PUBLIC LIBE
The focal length is 15 cm.?
g® sizə
A
Object size /
3
Sage distance
Object distance
since
.
•
1
In moving the lens 4 ft.
towards the wall,!
Fanother sharp image is formed
+
1
1
-
--
· L
-
1
1
OF
·
12-
squating (1) and (3))
C -
A
་
- 48
·
~48 16v
g2_-_16v_~__ 48}
(2)
From the graph, 3 - 0 - X,
(where y *
1
* X *
~ and a
+
-
U 3
and, u♥ • 50!
5
"
• 30
3
24
- 30
3
u - 45
since
1.1
1 .
and the image is real
1
•
-
45 15
114
Ans. The focal length is lig cầ.
Focal length of iena – Irt./ Cbject distance. = u ft.
ige distance ▼ft.
8 ft.
The focal lens of the convex lens is ij të
Chaestioma for naxs work)
29. (a) Draw a labelled diagram of a me
(b) Compare and contrast an eye with'
Fei What are common defects of vision and now
they are corrected?
(d) Explain, with the aid of a diagram, tha construction and aetion of a grossation lantern..
30. (4) What is a pure spectrum??
(b) in the forumtion of spectrum of" white light"
by a priam (1) which colour is deviated lanas (11) which colour mom t?
(6) State and accout for the differen
produced when (1) yellow azid blús (11) yellow and bine lights are mẤN d) White light is viewed through piese and yellow glass in sontset with The yellow glass transmita red, police green.
Describe the view (1) if the bius class transsita green, blue and violeta: (zág blue glass transmite red, green ARG