1.2.4 Data Storage (Binary, Hex, Shifts) & Data Representation

Question 1

What is 0101 in denary? (1)

Answer 1

5

Question 2

What is 11001111 in denary? (1)

Answer 2

207

Question 3

What is 151 in binary? (2)

Answer 3

10010111 (1 mark per nibble)

Question 4

What are the rules of binary addition? (4)

Answer 4

0 + 0 = 0. 0 + 1 = 1. 1 + 1 = 0 carry 1. 1 + 1 + 1 = 1 carry 1.

Question 5

What is an overflow error? (2)

Answer 5

An extra carry bit (1) that cannot fit into the bits provided (1).

Question 6

Convert 39 from hexadecimal to denary (1)

Answer 6

57

Question 7

Convert 203 from denary to hexadecimal (2)

Answer 7

CB (one mark per digit)

Question 8

Convert 10010011 from binary to hexadecimal (2)

Answer 8

93 (one mark per digit)

Question 9

Convert FA from hexadecimal to binary (2)

Answer 9

11111010 (one mark per nibble)

Question 10

How can you multiply a binary number by 2? (1)

Answer 10

Move all of the bits 1 place to the left.

Question 11

How can you divide a binary number by 2? (1)

Answer 11

Move all the bits 1 place to the right.

Question 12

What is a character set? (1)

Answer 12

The characters a computer system understands / displays.

Question 13

How many potential characters can you store with a byte? (1)

Answer 13

256

Question 14

How many potential characters can you store with 7 bits? (1)

Answer 14

128

Question 15

How many characters can ASCII represent? (1)

Answer 15

128

Question 16

How many characters can Unicode represent? (1)

Answer 16

256

Question 17

If the binary code for “A” was 65 what would be the code for “D”?

Answer 17

68

Question 18

Describe how a character set would be used to store the string “Hello world!” (2)

Answer 18

Each character in a character set has a unique binary value. (1) The binary values of each character are recalled in order. (1)

Question 19

How are images stored in binary? (3)

Answer 19

The image is split up into pixels. (1) Each pixel is given a binary code. (1) Which represents the colour of that pixel. (1)

Question 20

What is metadata? (1)

Answer 20

Data about data. Data about an image / sound file.

Question 21

What might metadata store about an image? (2)

Answer 21

Height (1) width (1) colour depth (1) resolution (1) author (1)

Question 22

What is the impact of increasing colour depth on an image file? (2)

Answer 22

More colours will be available (1) file size will increase (1)

Question 23

What is the impact of increasing resolution of an image file? (2)

Answer 23

More pixels will be used, increasing the detail of the image. (1) The file size will increase (1)

Question 24

How is sound stored in binary? (2)

Answer 24

The height of the sound wave is sampled at regular intervals (1) and converted to binary (1)

Question 25

What is the impact of increasing the bit depth on an audio file? (2)

Answer 25

The sound reproduced will be closer to the original (1) but file size will increase (1)

Question 26

What is the impact of increasing the sample rate of an audio file? (2)

Answer 26

The wavelength is sampled more often so the sound reproduced will be closer to the original (1) but file size will increase (1)