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18 - Final Test

 1. How many bytes are there per character in a text file?

  1

  3

  4

  2

 2. Which is the smallest of these data capacities?

  0.5 MB

  2KB

  2049 bytes

  4GB

 3. Which formulae can be used to estimate the file size of an image?

  number of pixels wide * number of bytes per pixel * number of pixels * 1.1

  number of pixels * number of bytes per pixel

  number of pixels * 1.1

  number of pixels wide * number of pixels high * number of bytes per pixel * 1.1

 4. Which formulae can be used to estimate the file size of a sound file?

  None of the above

  bytes per sample * channels * height + number of minutes

  samples per second * bytes per sample * duration

  samples per second * number of seconds * 1.1

 5. How many bytes are needed to store 32769 different colours?

  4

  1

  2

  3

 6. How many bytes are used in Unicode?

  2

  3

  1

  4

 7. The ASCII code is represented using 16 bits

  FALSE

  TRUE

 8. What is the maximum number of values that can be represented in 8 bits?

  None of the above

  18

  12

  256

 9. What is the maximum number of values that can be represented in 7 bits?

  100

  53

  23

  128

 10. A character set is the possible characters that can be represented by a computer system

  FALSE

  TRUE

 11. The result of the binary addition 0110 + 0101 = 1011.

  TRUE

  FALSE

 12. Overflow occurs when the pattern of bits is too small to be represented by the number of bits available in a register.
 It is also used to describe a machine code program that crashes.

  TRUE

  FALSE

 13. 11010100 in binary would be E4 in Hex

  FALSE

  TRUE

 14. What is 011 in Decimal?

  2

  1

  4

  3

 15. What is 0000 in Decimal?

  Error - you cannot have a binary number with only zeroes

  1

  0

  2

 16. What is this definition describing: The time period between taking samples/measurements. The more frequently the sound is sampled, the better the quality of playback

  sampling of data

  bit sampling

  sampling

  sample interval

 17. A gigabyte is 1024 megabytes / 230 bytes

  FALSE

  TRUE

 18. A nibble or nybble is 2 bits

  FALSE

  TRUE

 19. Extended Binary Coded Decimal Interchange Code: an 8-bit character set used by older mainframes.

  TRUE

  FALSE

 20. Short for picture element. It is the smallest component of a bit-mapped image.

  bit

  pixel

  bit pattern

  bitmap

 21. Analogue to Digital converter: takes real-world analogue data and converts it to a binary representation that can be stored on a computer

  DAC

  ADV

  ADC

  None of the above

 22. Data about data is referred to as:

  metadata

  information

  knowledge

  nonsense

 23. What is a 106 in Hexadecimal?

  23

  2A

  123

  6A

 24. 8 bits = 2 bytes

  TRUE

  FALSE

 25. Sound waves are ________ which means they are continuously changing.

  high

  analogue

  mixed

  digital

 26. The number of bits used to store each sample. The more bits used the better the accuracy of the sound file

  sample interval

  sample resolution

  None of the above

  sample rate

 27. The largest value you can have with four bits is:

  1101

  1010

  1111

  1000

 28. What is the result in binary after doing the left shift?
Binary Shift Example
=====================
The below number is no. 32 in Decimal. We want to multiply by 2.

Shift every bit to the left by one and insert a zero to the 
rightmost bit. The original leftmost bit is discarded.

128   64     32     16    8     4     2    1
=============================================
0     0      1     0     0    0    0    0

What is the Result in Binary?
======

128   64     32     16    8     4     2    1
=============================================
?     ?       ?      ?    ?     ?     ?    ?

  1000000

  10000000

  11100101

  11110001

 29. If we wish to ______ we shift every bit to the left by one and insert a zero to the rightmost bit. The original leftmost bit is discarded.

  multiply

  add

  subtract

  divide

 30. In decimal, you have the number 468, which is 111010100 in Binary. Shift it to the left to multiply by two and what happens?
Binary Shift Example
=====================
The below number is 468 in Decimal. We want to multiply by 2.

Shift every bit to the left by one and insert a zero to the 
rightmost bit. The original leftmost bit is discarded.

256   128   64     32     16    8     4     2    1
==================================================
1     1      1       0    1     0     1    0    0

What is the Result in Binary?
=============================
256   128   64     32     16    8     4     2    1
==================================================
???????????????????????????????????????????????????

  none of the above

  You would get a result of 110101000 which is 424 - an overflow error has occurred

  Nothing spectacular. It will work as expected

  It will add instead of multiply the numbers

 31. In the following example, can you spot the error. We are trying to divide 8 using binary shift.
The video will help, but you do not need it to answer the question.                                    Binary Shift Example
=====================
The below number is 8 in Decimal. We want to divide by 2.

Shift every bit to the right by one.
The original rightmost bit is discarded.

256   128   64     32     16    8     4     2    1
==================================================
0     0      0     0      0     1     0    0    0

What is the Result in Binary?
=============================
256   128   64     32     16    8     4     2    1
==================================================
 0     0     0      0      1    0     0     0    0 

  none of the above

  a single left shift has been applied instead of a single right shift

  a single right shift has been applied but the result has not been added to another bit of '1'

  two right shifts were necessary in order for the division to take place

 32. Can you spot the error in this binary shift (division)?
Binary Shift Example
=====================
The below number is 16 in Decimal. We want to divide by 4.

4 is 2 to the power of 2 (so we shift of two times to the right)

Shift every bit to the right by two. The original rightmost bit is discarded.

256   128   64     32     16    8     4     2    1
==================================================
0     0      0     0      1     0     0    0    0

What is the Result in Binary?
=============================
256   128   64     32     16    8     4     2    1
==================================================
 0     0     0      0      0    0     1     0    0 

= 4 in Decimal. 

  The shift should have been just once to the right

  The shift should have been one twice to the left, not right.

  The shift should have been one to the right, and the right most bit should not have been discarded but added to 1

  There is no error. The calculation and shift has been performed correctly

 33. What statement is true about this lossy compression of images?
datarep_compression_q1.jpg

  None of the above

  Compression has reduced the quality by a significant degree and should not be used

  They are vastly different and hugely matter

  It is slightly more blurry but not enough to matter in most circumstances

 34. What is the benefit of compressing an image file for a use on a website?

  It takes up less storage space on your website

  It may offer the user speed in loading the page for a very slighy quality reduction

  it would render five times faster

  All of the above

 35. A film could take up to an hour to download in uncompressed format whilst a compressed file could take just 12 minutes

  FALSE

  TRUE

 36. Lossless compression is when…

  reducing a file's size with NO loss of quality

  reducing file size with a massive reduction in quality

  reduing a file's size in exactly the same was as lossy compression

  reducing file size with an increase in quality

 37. Fill in the blanks for RLE
RLE
===================================================
One of the simplest examples of compression is RLE. 
RLE is a basic form of data compression that converts 
consecutive identical values into a code consisting of
 the character and the number __________________________________.
The more similar values there are, the more values can be compressed. 
The sequence of data is stored as a single value and count.

  marking the length of the run.

  marking the number of times the file has been compressed

  marking the number of bits contained in the file

  marking the binary file size

 38. In the following picture we compress …
datarep_compression_q3.jpg

  consecutive pixels by only replacing each run with one pixel from it and a counter showing how many items it contains.

  random pixels by replacing each run with several pixels from it

  nothing at all

  random pixels by replacing each run by four pixels from it.

 39. Run-length encoding isn’t a very effective option when compressing texts, but for images …
datarep_compression_q4.jpg

  where long runs of the identical pixels happen to occur it is quite useful.

  where short runs of text bits happen to occur in sequence, it is useful

  None of the above

  where there are pixels it is even less useful

 40. In "Peter Piper picked a peck of pickled peppers" the total no. of characters is ….

  44 (including spaces)

  33 (spaces are never included in calculations)

  23 (including spaces)

  22 (excluding spaces)

 41. A group of four bits, or half a byte, is sometimes called a ____________________

  kilobyte or megabyte

  nibble or nybble.

  byte or bit

  terrabyte or gigabyte

 42. 1 byte refers to …

  1 bit

  8 bits

  2 bits

  5 bits

 43. 1 byte can be used to store

   page of text from a novel

  one mp3 song

  114 minutes of DVD Video

  a number from 0 to 255

 44. This shows a memory stick with….
datarep_unitsofinformation_q1.jpg

  16 GB of memory

  32 bits of memory

  16 bytes of memory

  No memory

 45. bits, bytes, megabytes, gigabytes, terabytes etc are all used to…

  describe disk space, data storage or the capacity of system memory

  hold the parts of a computer together

  create the mother board

  perform calculations and store memory

 46. A bit can be used to:

  store a single number up to the value of 255

  store a single number up to the value of 55

  store a single letter like A

  hold the answer to a yes/no or true/false question

 47. A byte can be used to

  store the letter 'C'

  store a number from 0 to 255

  store a single letter like A

  All the listed options are correct

 48. The symbol for byte is uppercase B. 16 bytes would be written as

  16Bi

  16BYTES

  16B

  16MB

 49. A kilobyte is thought of as approximately 1000 bytes but to be accurate it is:

  2024 bytes (which is 2 to the power of 10)

  12 bytes

  102 bytes

  1024 bytes (2 to the power of 10)

 50. Have a look at the table below which shows the units of information leading to memory. Fill in the blanks
datarep_unitsofinformation_q2.jpg

  1024 TB

  1000 Bytes

  1024 GB

  None of the above