F2 IS 2nd Term WS13 Answers

2nd Term WS 13 Submission date：_____________ Name：______________________ Class & no.：2 _________(     )

11.3    Limitations of our eyes

11.4    Eye defects     

i      Words to know:

	English term	Write the words again	Chinese term
1	Limitation		限制
2	Telescope		望遠鏡
3	Microscope		顥微鏡
4	Blind spot		盲點
5	Eye defects		眼睛毛病
6	Short / Long sight		近 / 遠視
7	Near / Distant		近 / 遠
8	Concave / Convex lens		凹 / 凸透鏡
9	Cataracts		白內障
10	Artificial lens		人工晶體
11	Colour-blindness		色盲
11	Hereditary disease		遺傳病

i    Fill in the blanks:

1          Our eyes have limitations. We cannot see object clearly when they are too close / large

         or too large / close or too small.

2          We can use suitable instruments to extend our vision. For example, we can use ______________________

l   microscope to observe objects that are too small like bacteria;

l   telescope to observe objects that are too far away such as stars.

3           The light from the object focused on the blind spot produces no sense of sight because

there are no light receptors on this area.

4          Besides limitations of our eyes, if we have an eye defect, we cannot see things clearly. The followings are some examples:

l   short sight

l   Long sight

l  cataract

l   Colour-blindness

5           Two common eye defects are short sight and long sight which can be corrected by wearing spectacles with suitable lenses.

6           The lens of an eye is normally clear / colourless / transparent. If the lens becomes cloudy, vision becomes unclear.

This eye defect is called a cataract. It can be treated by replacing the cloudy lens with an

artificial lens.

7           Colour-blindness is a kind of eye defect that the patients cannot distinguish certain colours.

The most common one is red-green colour-blindness – the patient cannot distinguish between red and green.

It is caused by defects in or the absence of certain cones on the retina.

It is a hereditary disease and cannot be cured.

Final Examination Revision Exercise III (Answers)

Concept Checking

1.            T	2.             F	3.             F	4.             F	5.             T
6.            T	7.             F	8.             F	9.             T	10.           F
11.          T	12.           F	13.           F	14.           F	15.           T
16.          F	17.           F	18.           F	19.           T	20.           F

Multiple Choice Questions

1.            B	2.             C	3.             D	4.             B	5.             C
6.            D	7.             D	8.             C	9.             A	10.           D
11.          C	12.           B	13.           B	14.           D	15.           B
16.          B	17.           B	18.           A	19.           B	20.           D

Fill in the Blanks

1.   (a)                            sour                                                   (b)            lactic       

      (c)                            citric                                                 

2.   (a)                   eye-wash bottle                                          (b)            slow running water

3.   (a)                            blue                                                   (b)            red  

4    ___                      pH meter                      

5.   (a)                             low                                                   (b)            low 

6.   (a)                        hydrogen                                               (b)            burning splint 

7.   (a)         calcium carbonate                         (b)    carbon dioxide           (c)            lime water      

8.   (a)                   Sulphur dioxide                                 (b)            nitrogen oxides               (any order)

9.   (a)    solar energy / hydroelectric energy           (any one or other reasonable answers)

      (b)                             low                          

10.                     catalytic converters               

F2 IS 2nd term QZ 10 (11.2) ans

Word Translation (8 marks)

i    Write down the English terms of the following Chinese terms:

	Chinese term	English term
1	角膜	Cornea
2	虹膜	Iris
3	瞳孔	Pupil
4	晶狀體	Lens
5	視網膜	Retina
6	黃點	Yellow spot
7	盲點	Blind spot
8	視神經	Optic nerve

Label the diagrams (15 marks)

1. Eye lid                                      2. Eye lashes

3. Cornea                                     4. Pupil

5. Iris                                           6. White protective layer

7. Cornea                                     8. Iris

9. Pupil                                        10. Lens

11. Retina                                    12. White protective layer

13. Yellow spot                            14. Blind spot

14. Optic nerve

Fill in the Blanks (12 marks)

1        (1)Lens is a colourless layer which protects the eye and allow light to pass through. It also helps to focus light onto the retina.

2        (2)Pupil is a hole which allows light to enter the eye. In bright light, it becomes

(3)smaller so that less light is allowed to enter the eyes. In (4)dim light,

it becomes larger so that more (5)light can enter the eyes. Is size is controlled by (6)iris.

3        (7)Lens allows light to pass through. Its thickness can be changed so as to focus light onto the

(8)retina, which produces and send signals to the brain through (9)optic nerve.

4        (10)Yellow spot is the part of the retina which contains most light receptors and gives

clearest vision. However, (11)blind spot does not contain any light receptors and gives no vision even an image is formed on it.

5        (12)White protective layer protects the eyeball and give it shape.

Challenging Questions (Bonus 2 marks)

1.      Why is it important for the pupil to become smaller under bright light?

This can reduce the amounts of light entering the eye so as to

prevent the retina from being damaged by the strong light.

2.      How can the eye focus the light from the objects at different distances onto the retina?

The lens changes its thickness so that the light from the objects at different

distances can be focused and form sharp images on the retina.