# Homework 1 Data Representation Questions by iarthur

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```									Complete in your homework jotter and hand in on Thursday 3rd
Sept

1. ASCII and UNICODE are both used to represent text in computer
systems

(a) Describe 1 advantage of UNICODE over ASCII                          1

(b) Describe 1 disadvantage of UNICODE over ASCII                       1

2. What is the 8 bit two’s complement representation of the number -72?

1
3. In floating point notation what defines:

(a) The range of the numbers stored?                                    1

(b) The precision or accuracy of the numbers stored?                    1

4. Describe how graphics are stored using a bit-mapped package          2

5. (a) What is the number 385 represented as a binary number?           1

(b) Represent the number -86 in 8 bit two’s complement                  1

(c) Write the number -37 as an 8-bit binary number using 2s complement
1
6. Ian purchases a new scanner. He scans photographs saving them as a
bit mapped image.

(a) Ian is aware that the quality of a bit mapped image depends on its bit
depth and resolution. What is meant by the terms:

(i) bit depth?                                                          1
(i) resolution?                                                        1

(b) Ian scans a photograph. The image is 800 by 600 pixels and uses
65,536 colours. Calculate the file size of the scanned image. Show all

7. John uses his digital camera to take photographs. It has a 512
Megabyte memory card. His camera uses 16,777,216 colours and is set to
a resolution of 3000 x 2000 pixels

(a) Calculate the file size of a single image. Your answer should be in
appropriate units. Show all working                                     3

(b) What is the maximum number of images of this size that can be stored
on John’s memory card?                                               2

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