# 04 - Data Capacity and Calculating Storage

1. How many bits are there per character?
```Given the below what would your answer be?
===========================================
An ASCII character in 8-bit ASCII encoding is 8 bits (1 byte),
though it can fit in 7 bits.

An ISO-8895-1 character in ISO-8859-1 encoding is 8 bits (1 byte).
A Unicode character in UTF-8 encoding is between 8 bits (1 byte) and
32 bits (4 bytes).

A Unicode character in UTF-16 encoding is between 16 (2 bytes) and 32
bits (4 bytes), though most of the common characters take 16 bits.
This is the encoding used by Windows internally.

A Unicode character in UTF-32 encoding is always 32 bits (4 bytes).

An ASCII character in UTF-8 is 8 bits (1 byte), and in UTF-16 - 16 bits.
The additional (non-ASCII) characters in ISO-8895-1 (0xA0-0xFF) would
take 16 bits in UTF-8 and UTF-16.```

Always 256 bits

Always 12 bits

Always 1 bit per character

It depends what the character is and what encoding it is in (8 bits for extended ASCII)

2. In "Peter Piper picked a peck of pickled peppers" the total number of characters is ….

33 (spaces are never included in calculations)

44 (including spaces)

23 (including spaces)

22 (excluding spaces)

3. In normal ASCII encoding a bit of text that had 44 characters (including spaces) would require:

10 bits per character making a a total of 44 x 10 = 440

8 bits per character making a total of 352 bits

1 bit per character making a total of 44 bits

4 bits per character making a total of 44 x 4

4. To recap: each character in an ASCII file uses 7 bits but most files use extended ASCII which is ___________________.

4 bits per character

14 (double) bits per character

8 bits per character

2 bits per character

5. To calculate the file size of an ASCII text file, count the number of characters, including spaces and that will be ______________.

the number of bits in the file

the number of MB in the file

the number of KB in the file

the number of bytes in the file

6. Once you have found the number of bytes contained in a file, to find the number of bits you just need to:

multiply the number of bytes by itself

multiply the number of bytes by 8

none of these options

multiply the number of bytes by 256

7. The ASCII file size in bits =

number of characters x number of bits

number of characters x 2

number of characters x 8

number of characters

8. How many bits and bytes are in this sentence?

46 bytes and 290 bits

45 bytes and 280 bits

30 bytes and 339 bits

9 bytes and 78 bits

9. How many colours can be represented in an image with 8 bits?

None

25

256

33

10. The number of pixels in an image is worked out by: image width x image height (in pixels)

FALSE

TRUE

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

0.5

1.5

1

8

12. Which is the smallest of these data capacities?

1KB

2049 bytes

3GB

0.5MB

13. The sample frequency has no effect on the quality of a recording.

True

False

14. Which formula can be used to estimate the file size of an image?

Number of pixels * number of bytes per pixel

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

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

Number of pixels * 1.1

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

Bytes per sample * channels * height + number of minutes

Samples per second * number of seconds * 1.1

Samples per second * bytes per sample * duration

Samples per second * samples per second * channels * duration

16. Just two bytes are needed to store 32,769 different colours?

True

False

17. A file's size can be influenced by a number of factors but ultimately the more information a file stores, the smaller it will be.

False

True

18. A sound engineer is recording a 30 second mono sound clip of some crows cawing outside the studio. Her recording equipment samples at 10 kHz and she is using 8-bit sampling. How big will the sound file be in bytes?

200 bytes

2,400,000 bytes

3000 bytes

300,000 bytes

19. A sound recording will last for 10 seconds. It will need four microphones (i.e. four channels of sound needed) and for a good quality of sound, 16-bit sampling will be used at 5000 Hz frequency. How big will the sound file be in bytes?

5,000 x 16 x 10 = 100,000 bytes

5 x 10 = 50 x 16 = 1,560,000 bytes

It cannot be calculated

5,000 x 16 x 10 = 800,000 bytes

20. An old recording has a size of 2.2 MB. The label on the box says that it was recorded in mono (one channel), that it had a recording sampling frequency of 20 kHz and used 8-bit sampling. How long would this piece of music last?

110 seconds

20,000 seconds

4 seconds

10,000 seconds