Paper 1

Question 1

Explain the term algorithm

Answer 1

`An algorithm is a seirs of steps that can be folloed to complete a task.

Question 2

Understand a computer program is…

Answer 2

an implementation of an algorithm.

Question 3

Explain the terms:

1) Abstraction
2) Decomposition

Answer 3

1) Abstraction involves removing unnecessary details ffrom a problem in order ro solve it.
2) Decomposition involves the breaking down of a problem into smaller, simpler steps or stages.

Question 4

Be able to solve problems using pseudocode or flowcharts

Answer 4

Give an example.

Page 6 - 12 of the Tecbook in classroom

Question 5

Identify simple inputs, processes and outputs in algorithms

Answer 5

Input data - for example, ask the user a question or
collect a value from a sensor.

Process data - for example, add two values together or make a decision when a value reaches a certain amount.

Output data - display some results or play a sound.

Question 6

Define the purpose of simple algorithms

Answer 6

Simple algorithms process inputted data and give an output.

Question 7

Recognise that more than one algorithm can solve the same problem

Answer 7

Give examples

Question 8

Compare algorithms based on their efficiency

Answer 8

Give examples

Question 9

Explain how the linear search algorithm works

Answer 9

A linear search is when you search every single item in the list for a certain number. If you need the biggest or smallest numbers you need to search the whole list, but if you are looking for a certain number you only need to search the list until you find it.

Question 10

Explain how the binary search algorithm works

Answer 10

A binary search is when you search for a certain number in a sorted list by halfing the list discarding the half too big or too small until you are left with the number you want to find,

Question 11

Compare and contrast linear and binary algorithms

Answer 11

Linear searches can be performed in any list of numbers.
Binary searches can oly be performed on a sorted list.

Linear searches may work well on smaller list, but Binary searches are much quicker in big lists (most of the time)

Question 12

Explain how the merge sort algorithm works

Answer 12

This is a two stage sort.
The first stage devides the list (by 2) forming a sublist, until each sublist is of one lenghth long.
The second stage repeatedly merges the sublist to produce a new sorted sublist until there is only one sublist remaining.Merging the final two sublists results in the sorted list.

Question 13

Explain how the bubble sort algorithm works

Answer 13

A bubble sort works by reoeatedly going through the list to be sorted comparing each pair of adjacent elements. If the elements are in the wrong order they are swapped. This is doen in passes until the whole list is sorted but the computer must check this by compleating a final pass.

Question 14

Compare and contrast the bubble and merge sort algorithms

Answer 14

The bubble sort algorithm is very slow and inefficient for sorting more than a very few items, wheras the merge sort is relitivly qucker.
On the other hand, the bubble sort algorithm is much simpler and easyer to understand for the coder than the merge sort algoritm.

Question 15

Explain the concept of a data type

Answer 15

Any data that a program uses must be stored in memory locations, each given its own identifier while the program is running. Data types are diffent types of data and are catogries we sort data into.

Question 16

List and describe the 5 common data types

Answer 16

Integer- A whole number such as: 3, 45, -453
Float/Real- A number with a fractional part such as: 34.456, -9.2, 10.4, Pi(3.14159265…)
Character- A single character, where a character can be any letter, digit, punctuation mark or symbol that can be typed.

Question 17

Describe how variable declaration is used in programs

Answer 17

In some programming languuages variables are decleared at the star of a progrtam so that when the program runs, the appropriate amount of memory can be reserved to store the data

Question 18

Describe how constant declaration is used in programs

Answer 18

In some programs, there are certain values that can remain the same while the program runs. Constants are declared at the start of a program and can then be referred to as needed in the code

Question 19

Describe how assignment is used in programs

Answer 19

In most programing languages, values are assigned to variables using an ‘=’ sign.
In pseudocode, we will use the ‘<==’ symbol to mean assignment

Question 20

Describe how iteration is used in programs

Answer 20

There are two basic iteration constructs:
For Loop- allows you to exercute a group of steps a specific number of times.
While Loop- allows you to exercute a group of steps until a specific condition is met or not met.

Question 21

Describe how subroutines are used in programs

Answer 21

A subroutine is a named, self-contained section of code that performs a specific task. It may reurn one or more valuses but doesn’t have to.

Question 22

Understand what a pixel is

Answer 22

A pixel is a single point in an image, which can have its colour set independently

Question 23

Be able to describe how pixels relate to an image

Answer 23

The more pixels you have the more detail you image has

Question 24

Be able to describe the way images are displayed

Answer 24

Images are displayed by individual pixels turning on or off, turning on with different colours makes the image colourful.

Question 25

Image file size =

Answer 25

resolution x colour depth

Question 26

Sound file size=

Answer 26

sample rate x sample size x time (s)

Question 27

what are the layers of the TCP/IP model and what do they do?

Answer 27

Application- where the user operates
Transport- establishes an end to end connection to the recipient computer. Data is then split into packets and labels it
Network- adds the destination and source IP address
Link- provides the physical link tot he network. It also adds the MAC address of the source and the next devices.