Flashcards in 3.5 Deck (63)

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1

## What is a natural number? (N)

### is a whole number that is used in counting (0,1,2,3,4,5,6,7,8,9)

2

## What is a rational number? (Q)

### any value that can be expressed as a ratio or a fraction. Includes integer values e.g. 3/1, 6.74/1000

3

## What is an irrational number? (Q')

### a value that cannot be expressed as a fraction and has an endless series of non-repeating digits. e.g. pi - 3.1415

4

## What is an integer number? (Z)

### a whole number that could be positive or negative e.g. -2,-1,0,1,2

5

## What is a real number? (R)

### any number that is natural, rational or irrational. The set of real numbers is the set of all possible real-world quantities.

6

## What is an ordinal number?

### to describe the numerical position of the object e.g. 1st, 2nd, 3rd

7

## What are natural and real numbers for?

###
natural numbers - for counting

real numbers - for measurement

8

## How do you find the number of bits in binary?

### 2^{n-1}

9

## How many bits in 1 byte

### 8 bits

10

##
Fill the gaps

nibble, ____, byte, __, MB, __, TB, __

### Nibble, bite, byte KB, MB, GB, TB, PB

11

## What does ASCII stand for?

### American Standard Code for Information Interchange

12

## Computers use Two's complement to represent what two numbers?

### Positive & negative numbers

13

## What is fixed point binary?

### There is a fixed number of digits after the decimal point

14

## What is fixed point binary used for?

### For displaying decimal numbers (this makes the number more exact)

15

## One advantage of fixed point binary?

### it stores the number accurately

16

## One negative of fixed point binary?

### Cannot represent wide range of numbers in the same number of bits e.g. 4000 or 0.0001

17

## What is the difference between signed and unsigned binary?

### Signed binary means that the item can hold positive or negative values. Unsigned binary doesn't distinguish between positive and negative values.

18

## In unsigned binary, what is the minimum & maximum value for a given number of bits (n)?

### 2^{n-1} & 0

19

## What is Ascii & Unicode?

###
Ascii uses an 8-bit encoding while Unicode uses a variable bit encoding.

Unicode is standardized while ASCII isn't.

Unicode represents most written languages in the world while ASCII does not.

20

## Why is error checking used?

### because bits can change during transmission because of interference

21

## What are the 3 forms of error checking & correction?

###
- Parity bits

- Majority voting

- Check digits

22

## What is parity bits?

### a bit which acts as a check on a set of binary values, calculated in such a way that the number of 1s in the set plus the parity bit should always be even (or occasionally, should always be odd).

23

## What is majority voting?

###
it selects put error & takes the majority to correct the error

data = 1011

transmission = 111 000 111 111

received = 101 001 110 111

24

## What is Metadata?

###
'data about data'

e.g. file name, date created, resolution, colour depth, creator

25

## What are the two forms sound is stored in?

###
Analogue = infinite amount of binary

Digital = binary which computers understand

26

## How do we convert analogue to digital?

### We use a ADC (analogue to digital converter)

27

## What is the ADC process?

### Sound waves --> electrical voltage --> binary data

28

## How do we convert digital to analogue?

### We use a DAC (digital to analogue converter)

29

## What is the DAC process?

### binary data --> electrical voltage --> sound waves

30