GCSE Computer Science: Data & Binary Quiz

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• Computing
• Upper Secondary (Key Stage 4)
• GCSE

GCSE Computer Science: Data & Binary Quiz

What is a bit?

A

A) Storage unit

B

D) Sound sample

C

B) Binary digit

D

C) Compression method

What is the size of a byte?

A

8 bits

B

4 bits

C

1024 bits

D

6 bits

Match the unit 'megabyte' to its byte equivalent.

A

1024 MB

B

1024 GB

C

1024 bytes

D

1024 KB

What does 0000 0110 represent in decimal?

A

6

B

10

C

15

D

12

What is the decimal value of 0000 1011?

A

12

B

10

C

11

D

9

What is 0110 + 0011 in binary?

A

1010

B

0111

C

1100

D

1001

What is 15 in hexadecimal?

A

C) D

B

D) 15

C

B) E

D

A) F

What is the decimal value of 2A (hex)?

A

32

B

42

C

26

D

36

What is a pixel?

A

D) Measurement of sound

B

A) A font type

C

C) A colour palette

D

B) The smallest image part

What does 'colour depth' mean?

A

The number of colours in an image

B

A type of font

C

A measure of brightness

D

Image size in pixels

What is the file size of a 10x10 image at 4 bits per pixel?

A

800 bits

B

400 bits

C

100 bits

D

200 bits

What does sample rate refer to?

A

Volume of sound

B

Number of samples per second

C

Sound quality

D

Number of bits per sample

Sample rate=2Hz, bit depth=8 bits, length=5s, mono. What is the file size in bits?

What is the audio file size in bits?

A

160 bits

B

40 bits

C

80 bits

D

200 bits

Which format is lossy compression?

A

JPEG

B

ZIP

C

MP3

D

PNG

Which format is lossless compression?

A

MP3

B

ZIP

C

PNG

D

JPEG

What is the result of 8 bit binary addition
10111001 + 01000110?

A

11111111

B

11111111 (with overflow)

C

11111100

D

11111100 (with overflow)

What is the result of 8 bit binary addition

11010110 + 00101101?

A

00000011 (with overflow)

B

11111100

C

00000010 (with overflow)

D

11110011

What is the result of 8 bit binary addition

11101101 + 01011110?

A

01001011 (with overflow)

B

01001010

C

01001011

D

01001010 (with overflow)

What is the hexadecimal value of 11011101?

A

A. DD

B

D. CD

C

B. DE

D

C. DF

Which binary number matches the hexadecimal value 7B?

A

01101011

B

11111011

C

01111011

D

01111010

Time for the questions that separate the mortals from the Computer Scientists.

An image is 1200 pixels wide and 800 pixels high with a colour depth of 24 bits. What is the uncompressed file size in megabytes?

A

2.88 MB

B

28.8 MB

C

23.04 MB

D

19.2 MB

Total pixels: 1200 multiplied by 800 = 960000
Bits per pixel: 24
Total bits: 960000 multiplied by 24 = 23040000 bits
Convert to bytes: divide by 8 = 2880000 bytes
Convert to megabytes: divide by 1 000 000 = 2.88 MB

A 200 by 200 pixel image uses indexed colour with a palette of 64 colours. What is the minimum bit depth required and the total file size in bytes

A

6 bits per pixel, 240000 bytes

B

6 bits per pixel, 30000 bytes

C

7 bits per pixel, 30000 bytes

D

8 bits per pixel, 40000 bytes

64 colours needs 6 bits per pixel (because 2^6 = 64).
Total pixels: 200 multiplied by 200 = 40000
File size: 40000 multiplied by 6 = 240000 bits
Convert to bytes: divide by 8 = 30000 bytes.

A stereo recording uses a sample rate of 11025 Hz, bit depth of 8 bits, and lasts for 90 seconds. What is the file size in bytes?

A

1 984 500 bytes

B

1 984 500 bits

C

992 250 bytes

D

1 984 500 kilobytes

Why
Mono samples: 11025 multiplied by 90 = 992250
Stereo doubles it: 992250 multiplied by 2 = 1984500 samples
Bits per sample: 8
Total bits: 1984500 multiplied by 8 = 15876000
Convert to bytes: divide by 8 = 1 984 500 byte