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17 - Practice Test

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

ADV

ADC

DAC

None of the above

2. Data about data is referred to as:

metadata

nonsense

knowledge

information

3. What is a 106 in Hexadecimal?

123

4. 8 bits = 2 bytes

FALSE

TRUE

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

analogue

high

mixed

digital

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

None of the above

sample resolution

sample rate

sample interval

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

1101

1111

1000

1010

8. 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
=============================================
?     ?       ?      ?    ?     ?     ?    ?

11100101

11110001

10000000

1000000

9. 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

subtract

divide

add

10. 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

Nothing spectacular. It will work as expected

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

It will add instead of multiply the numbers

11. 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

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

none of the above

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

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

12. 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 one twice to the left, not right.

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

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

The shift should have been just once to the right

13. What statement is true about this lossy compression of images?

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

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

They are vastly different and hugely matter

None of the above

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

it would render five times faster

All of the above

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

It takes up less storage space on your website

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

TRUE

FALSE

16. Lossless compression is when…

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

reducing file size with a massive reduction in quality

reducing file size with an increase in quality

reducing a file's size with NO loss of quality

17. 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 number of times the file has been compressed

marking the number of bits contained in the file

marking the binary file size

marking the length of the run.

18. In the following picture we compress …

nothing at all

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

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

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

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

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

where there are pixels it is even less useful

None of the above

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

22 (excluding spaces)

33 (spaces are never included in calculations)

44 (including spaces)

23 (including spaces)

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

terrabyte or gigabyte

nibble or nybble.

byte or bit

kilobyte or megabyte

22. 1 byte refers to …

5 bits

2 bits

8 bits

1 bit

23. 1 byte can be used to store

114 minutes of DVD Video

one mp3 song

page of text from a novel

a number from 0 to 255

24. This shows a memory stick with….

16 bytes of memory

16 GB of memory

No memory

32 bits of memory

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

perform calculations and store memory

hold the parts of a computer together

create the mother board

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

26. A bit can be used to:

store a single number up to the value of 55

store a single number up to the value of 255

store a single letter like A

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

27. A byte can be used to

store a single letter like A

store the word 'CAT'

store an audio sequence with just 10 notes

store a number from 0 to 512 billion

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

16MB

16Bi

16BYTES

16B

29. 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)

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

1024 TB

1024 GB

None of the above

1000 Bytes

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