Chapter 1 Information representation

Question 1

What is a bit and what is its value?

Answer 1

One bit is the smallest unit of a computer memory and the value is 1 or 0.

Question 2

What is a byte?

Answer 2

One byte is a group of eight bits.

Question 3

How many bytes has one kilobyte?

Answer 3

1024 bytes.

Question 4

One megabyte how many kylobytes?

Answer 4

1024 kylobytes.

Question 5

One gigabyte how many megabytes?

Answer 5

1024 megabytes.

Question 6

What is the difference between denary and decimal number? What are the digits of this system.

Answer 6

Denary and decimal are synonims.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9.

Question 7

What are the digits of hexadecimal numbering system?

Answer 7

0 to 9, A to F

Question 8

How do you transform a denary number to a hexadecimal number for example 20?

Answer 8

20:16 = 1
20-16 = 4
4:1=4
Hexadecimal value = 0014

Question 9

What is the file extension of bitmap?

Answer 9

The file extension for bitmap is .bmp

Question 10

What is the file extension of a vector graphics image?

Answer 10

The file extension of a vector graphics image is .svg

Question 11

What is color depth?

Answer 11

Color depth is the number of colors that can be used in an image.

Question 12

How are pictures stored?

Answer 12

A picture is stored pixel by pixel(position and color):
The colors can be stored:
- 24 bit color - 16 million colors
- Monochrome ( one bit)
- 16 color (4 bit)
- 256 color (8 bit color)

Question 13

Audio formats.

Answer 13

WAV -high quality - very large
MP3 - Smaller suitable for websites
MIDI - The smallest and saves the recording like a piece of sheet music. It needs a music synthesizer.

Question 14

What does bit rate mean?

Answer 14

Bit rate means the number of bits used to store one second of sound or video.

Question 15

What does the bit rate depend on?

Answer 15

It depends on:

• sample rate (number of times the sound changes per second)
• number of channels (mono, stereo, quad etc.)
• bit depth (range of sound frequencies used or the range of different notes in a music.).

Question 16

How to determine bit rate(storage)?

Answer 16

sample rate x number of channels x bit depth = bit rate (storage)

Question 17

What is the difference between lossless and lossy comprassion.

Answer 17

In lossless compression the size of the file gets reduced like in lossy but, it doesn’t lose data quality.

Question 18

What could happen when sound is compressed?

Answer 18

The music might use fewer channels, have lower sample rate or to have reduced bit depth.

Question 19

How much is 1111 as an unsigned integer?

Answer 19

2^4-1=15

4 is the number of ones

Question 20

What is an unsigned integer?

Answer 20

An unsigned integer is a value that can’t be negative.

Question 21

What are signed integers?

Answer 21

Signed integers are values that can be negative

Question 22

How are signed integers usually stored?

Answer 22

Signed integers are usually stored using two’s complement or one’s complement.

Question 23

How does one’s complement work?

Answer 23

Switch the 0 -> 1 and 1 -> 0

Question 24

How to do two’s complement?

Answer 24

Do one’s complement first and then add 1
Or
Start from the least significant bit and leave all the 0s and the first 1 unchanged. Then, switch all the remaining bits.