Unit 8.1 Data Representation

Question 1

What is the highest number you can represent with 1 byte?

Answer 1

255

Question 2

How many bits are in one byte?

Answer 2

8

Question 3

What is the highest two’s complement number you can represent with 8 bits?

Answer 3

127

Question 4

What is the method for converting a binary number directly into Hexadecimal?

Answer 4

Split the 8 bits into two 4 bit nibbles.
Convert each nibble into a Denary number.
If either number is 10 - 15, convert to relevant letter.
Join the two conversions together.

Question 5

What are the range of characters for the Hexadecimal system?

Answer 5

0 - 9, A - F

Question 6

What base is the hexadecimal system?

Answer 6

16

Question 7

What does ASCII stand for?

Answer 7

American Standard Coding for Information Interchange

Question 8

What is the purpose of the ASCII system?

Answer 8

Standardised system for communicating text across the internet.

Question 9

What are the limitations of the ASCII system?

Answer 9

Cannot be used for all languages as it cannot represent all possible characters. For example, letters with accents.

Question 10

What is the smallest element of an image?

Answer 10

Pixel

Question 11

What is the colour depth of an image?

Answer 11

The number of colours available to each pixel.

Question 12

A 4 bit colour depth has how many colours?

Answer 12

16

Question 13

When converting to digital sound, the sample rate is the…?

Answer 13

The number of samples you take in one second.

Question 14

When converting to digital sound, the sample interval is the…?

Answer 14

Gaps between each of the samples.

Question 15

What are the effects of reducing the sample rate and sample interval?

Answer 15

Smaller size file but poorer quality sound.

Question 16

Convert FF from Hexadecimal to Denary.

Answer 16

255

Question 17

How many places are there between uppercase and lowercase letters?

Answer 17

32

Question 18

Convert 1001 1001 into Denary.

Answer 18

153