P.O.C.A. WONG SIU CHING SECONDARY SCHOOL

FORM FOUR SECOND TERM EXAMINATION 2005-2006

COMPUTER AND INFORMATION TECHNOLOGY

Paper 2 (MODULE D)

Question-Answer Book

9:55 am – 10:35 am (40 minutes)

23-6-2006

This Paper must be answered in English

Total no. of pages: 4

1.Write your Name, Class and Class Number in the spaces provided on this cover.

2.The Full marks is 40.

3.Answer all questions.

4.Show all your steps and workings clearly.

5. Write your answers in the spaces provided in this

Question-Answer Book.

6.Supplementary answer sheets will be supplied upon request. Write your name on each sheet.

Name
Class
Class Number
Paper 2 / Marks
1
2
3
4
5
6
Total

P. 1

1. (a)State TWO types of animations that can be shown in the web browsers, giving an example for each.

Bitmapped animation – e.g. animated GIF

Vector based animation – e.g. Flash movie

(2 marks)

(b)Compare the two types of animations in terms of

i) the resource requirements on the web browsers

Flash movie needs a Flash Player but Animated GIF does not

ii) the smoothness of the animation

Flash movie is better as the frame rate is higher.

iii) the colour depth

24-bit for Flash movie and 8-bit for Animated GIF

(3 marks)

2. Michael is responsible for maintaining a school web site. He has to upload some school documents such as parent letters onto the web site. He uses Portable Document Format (PDF) for the parent letters.

(a) Give two advantages of using PDF format over DOC format.

PDF format can be displayed in different OS, DOC format can only be seen in Windows environment.

PDF documents can only be read but cannot be changed but Word documents can be edited.

PDF reader is free to download but MS Word is not free.

(2 marks)

(b) Name the software required to read a PDF document.

Adobe Acrobat reader

(1 mark)

(c) Suggest one method for exporting documents as PDF files.

Export from OpenOffice directly/Convert to PDF format using conversion software

(1 mark)

3.Miss Yip is a sports teacher and she is in charge of the school annual Sports Day. She asks her student Betty to shoot certain sports events using a video camcorder with tapes on the Sports Day. Miss Yip wants to use the video for demonstration in future sports lessons. However, Betty suggests converting the tapes to digital video files and storing them on a computer.

(a) Give two advantages of using digitized video files over video tapes for

demonstration in lessons.

Easy to search the necessary files

Easy to edit the digitized files

(2 marks)

(b) Give four attributes of video that affect its file size.

Frame size

Frame rate

Colour depth

Duration

(4 marks)

4.(a) An artist has put a button on his own web page .

Suggest two situations in which it is better for a user to click on ‘Text Only’.

The user wants to see the text information quicker

The user’s computer does not support multimedia display

(2 marks)

(b) The designer of the web site would like to display a 1024 x 768 pixels graphic

at the center. However, the display of the graphic through the browser is not what he expected. Comment on the problem he has.

The viewing area in a browser is less than 1024 x 768 pixels

He should design the graphics according to the size of the viewing area.

(2 marks)

(c) The designer also put a button on the web page. When the

cursor is placed on the ‘Feedback’ button, the bottom status line on the browser shows mailto:. What happens when the user clicks on the mouse at this moment? Recommend another method to collect the feedback.

The e-mail software will be opened with the e-mail address placed on the receiver field.

Use an electronic message board.

(2 marks)

5.Mr. Lee’s web page contains many images. His friends find that it always takes a very long time to open the web page and ask Mr. Lee to optimize his images.

(a)In order to optimize an image file, one has to strike a balance between two

properties of an image file. What are these two properties?

File size

Quality

(2 marks)

(b)Most image files on Mr. Lee’s web page are in GIF format while the other are in JPEG format.

(i) How many colours do GIF format and JPEG format separately support?

GIF – 256 colours

JPEG – 16.7 million colours

(2 marks)

(ii) Describe two advantages of using GIF format other than supporting

animations.

support transparency

lossless compression

(2 marks)

(c)What is an animated GIF? How does it work?

A single file consists of several images

The images will be displayed one by one continuously to produce an animation effect.

(2 marks)

(d)Another image format, PNG, is also commonly found in web pages. Describe one advantage and one disadvantage of this image format.

Advantage: it supports 24-bit colours

Disadvantage: cannot support animation

(2 marks)

6.Audio sounds are captured and converted into digital data using a sound card before

they can be processed in a personal computer. This conversion process is called digitisation and the digitized data are commonly stored in WAVE file format. The quality of the sound reproduced depends on the sampling rate and the sample size of the digitisation process. Different sound qualities using different sampling rates and sample sizes are shown in the following table.

Sound Quality / Sampling Rate (kHz) / Sample Size (bits)
A / 8 / 8
B / 11.025 / 8
C / 22.05 / 16
D / 44.1 / 16

(a)What is the meaning of sampling rate? How does it affect the sound quality?

Sampling rate means how many times the sound is measured in one second.

The higher the sampling rate, the better is the sound quality.

(2 marks)

(b)What is the meaning of sample size? How does it affect the sound quality?

The number of bits used to record the sound is called the sample size.

The higher the sample size, the better is the sound quality.

(2 marks)

(c)Calculate the file size (uncompressed) of a one-second mono sound file of Sound Quality D

44.1 x 1000 x 16 / 8 bytes = 88200 bytes

(1 mark)

(d)Sound Quality A is usually used for telephone conversation. Explain briefly why.

Telephone conversion is mainly human speech

The maximum frequency of human speech is 4 kHz, the sampling rate of 8 kHz is enough.

(2 marks)

(e)Suggest one audio file format which is suitable for music composing and editing. Describe its main characteristics.

MIDI

A midi file only consists of the musical notes, the file size is very small.

(2 marks)

END OF PAPER

P. 1