COMPUTER STUDIES

PAPER 1 MARKING SCHEME

THEORY

KIPKELION EAST JOINT EVALUATION TEST 2022

SECTION A (40 MARKS)
ANSWER ALL THE QUESTIONS FROM THIS SECTION IN THE SPACES PROVIDED
1. One of the functions of an operating system is to control computer resources. State
three resources under operating system control (3 marks)
Processor
Input/output devices
Application programs
Storage devices
Communication devices and ports

2. (a) The figure below shows the relationship between tables in a database.

Table 1
Table3 1 ∞ Admno
Admno Termcode ∞ 1 Table 2
Name Termid
Idno
Class Year
Eng
maths

Identify two primary keys and two foreign keys used in the relationships (2 marks)
PK FK
AdmNo TermId
TermCode AdmNo

(b) Distinguish between bound and unbound controls as used in database forms (2 marks)
Bound controls are used to get data from a table or query while unbound controls do
not get data from a table/query/link.
3. Explain why an impact printer is suitable for printing multiple copies (2 marks)
They have special hammers that produce characters on a piece of paper. And
behind every paper, there is a coupon copy that produces characters on another
paper.
4. State any four examples of document readers (2 marks)
OBR
OMR

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OCR
MICR

5. (a) Define the term simulation (1 mark)

This is the process of creating a model of a real object/concept in order to
experiment the behavior of a real object using a computerized model
(b)List two educational areas where simulation programs can be used (1 mark)
Training drivers
Training pilots
Training engineers
6. Explain two ways of protecting data and information against un authorized access
(2
marks)
-Password protection –allows the user to open/ modify file/doc
-Data encryption-only authorized user can decipher the code
-User and group permission to user- user access levels
-Firewalls- filters data and information exchanged between different networks
-Security monitors-keeps tracks of activities performed using computer
systems e.g. CCTV
-Biometric security- only users whose attributes are identified can access

7. Explain two characteristics of good information (2 marks)

-Accuracy- should be as close to the actual value as possible
-Timeliness- should be available when needed
-Relevance- should be useful in order to give out the expected output
-Completeness

8. Explain three types of errors that are likely to exist in a program (3 marks)
-Syntax errors- errors as a result of incorrect use of a programming language e.g.
spelling, incorrect punctuation, use of reserved words etc.
-Logical errors-errors that prevent the program from doing what it is expected
to do
-Runtime errors- results in unexpected/ premature end of a program e.g. an
attempt to divide a number by zero
9. State two roles of a network admistrator (2 marks)
-Sets up a computer network
-Maintain and enforce security measures on the networks
-Monitor use of network resources
-Maintain and troubleshoot network related problems
10. State three negative impacts of information communication technology on the
environment (3 marks)
-The huge piles of garbage of dead computers and accessories causes pollution
-Massive extraction of mineral resources for making computer parts
-Energy consumption and radiation
-Disposal of nickel-cadmium laptop batteries contain cadmium which leaks to
the underground water table
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11. Study the follow flowchart then answer the questions that flow.
A

B
C
A

i. Identify the type of flowchart represented by the flowchart in figure(1 mark)

System flow chart

ii. Name the flowchart symbols labeled A, B,C and D in the flowchart. (2 marks)
A- Stored data
B- Screen output/ display
C- Manual input
D- Document/report
12. Mary a computer student noticed that every time a person enters the computer lab, the
computer screen flickered. Identify three reasons why the monitor might be flickering

(3marks)
- There maybe a loose connection to the computer hence flickering when
touched
-Cables maybe laid on the pathway hence flickering when stepped on.
-Electrical interference from other electrical nearby devices

13. (a) state the importance of column breaks as used in a word processor (1 mark)
Used to enforce an end of a column to start/ move the cursor at the beginning
of the next paragraph

(b) List any two line spacing specifications used in Ms- Word (1 mark)
-Single
-Double
-1.5
-multiple

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14. The first column in the table below contains the formula stored in cell C10 of a
spreadsheet. Enter the formula as they would appear when copied to cell F15 of the same
spreadsheet (2 marks)

FORMULA IN C10 FORMULA IN F15

=A5*B5 =D10*E10
=4*B$6 =4*E$6

15. (a) Differentiate between an analog and digital data signal (2 marks)
An analog data signal represents data that is continuous in nature while
digital signal represents data that is non- continuous in nature

(b) The government of Kenya is in the process of laying out fibre optic cables throughout
the country. State three advantages of fibre optic cables (3
marks)
-Not prone to electromagnetic interference
-Supports a high bandwidth
-Low attenuation thus suitable for long distance transmission
-Smaller and lighter than copper cables
-Do not generate electrical signals thus can be used in hazardous places

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SECTION B( 60 MARKS)
ANSWER QUESTION 16 AND ANY OTHER THREE QUESTIONS FROM THIS SECTION
16.(a) Draw a program flowchart that would accept and their sum. If the sum is greater
than 200, it adds 30 to the sum, otherwise subtracts 20 from the sum. The program should
then display the results (7 marks)

(b) Study the pseudo code below and determine its output (3 marks)
STEP 1: T=0
M=0
K=1
STEP 2 M=M+T
T=T+5
K=K+1
STEP 3 REPEAT STEP 2 WHILE K<3
WRITE M, T
EXIT

T M K M=5
0 0 1
5 0 2 T=10
10 5 3

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(c )(i)List two benefits of using interviews as a method of fact finding (2 marks)
-Users can express their opinions in a detailed way
-Non- verbal communication can be observed
-Questions can be paraphrased for clarification
(ii) Explain three types of system change over strategies (3 marks)
-Parallel- both the old and the new systems operate together for a
period of time before the old system is discarded.
-Direct- the old system is discarded and the new one implemented
immediately
-Phased- the old system is gradually replaced in stages by the new
system
-Pilot- a section of the organization runs the new system while the rest
runs the old system.

17. (a) state three functions of a database management system (DBMS) (3 marks)
- allows the user to add or delete records
-update or modify existing records
-organise data for easy access, retrieval and manipulation
-acts as an interface between the database and other applications
-enforce security for data in a database
-keep statistics of data items in a database
(b) if a database was to be created for a list, Tables, Forms, Queries and Reports are
likely to be used. State the purpose of each of the objects (4
marks)
-Table- for storing data
-Forms- data entry, editing and viewing the records
-Queries-extracting data used on some criteria/ performing calculations
-Reports- creating summaries for data/performing calculations
c) The information below is maintained by Jessica Fruit store. Study it and answer
the questions that follow:

Product Product name Qty in stock (kg) Value per unit

number (ksh)
001 Peach 1000 200
002 Oranges 1200 200
003 Mangoes 1300 100
004 Tomatoes 1200 140
005 Cabbages 1500 25
Write down the query statements you can use to list the following;
i) Product names starting with letter P. (2 marks)
Like P* or P* in query design window

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ii) Value per unit below 200. (2 marks)
<200 in query design window.

(d) The following is a spreadsheet relating to a farmer. [2 marks]

A function = IF (B2<200, “Not Viable”, IF (B2>300, “Moderate”, IF (B2>1000,

“Viable”))). Give the appropriate result returned in cells C2, C3, C4 and C5
A B C
1 Crop Amount Not viable
2 Maize 150 Not viable
3 Bean 300 Not viable
4 Cashew nuts 850 Moderate
5 Cabbages 1036 viable

d) Name four data types used in spreadsheets. (2 Marks)

-labels
- Values
- Formulae
- Functions

18. (a) Explain the use of the following commands found in the spell check dialog box in
reference to word processing (3 Marks)
i) Change – replace a word with a spelling error with the given suggestion
ii) Ignore once – leave a word with a spelling error without making any change
iii) Add – used to add a new vocabulary in a list of suggestions into

(b)State four font styles supported by Ms. Word (2marks)

 Bold
 Bold italics
 Italics regular
 Underline

(c) Work out the followingbinary arithmetic (2marks)

i. 11101.00112+ 101.0112

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11101.00112
+00101.01102
100010.10012

ii. 101001.101012-110.011012
101001.101012
000110.011012
100011.010002
iii. Using twos complement, perform the following calculation. (4marks)
2310 - 4110

23=000101112
41=001010012 1s complement=110101102
2s complement=110101112
23-41=000101112+110101112=111011102
{Decimal to binary conversions 1mark each (max 2)
1s complement ½ mark
2s complement ½ mark
Addition 1 mark}

iv. Convert 13.12510 to decimal. (2marks)

Whole number part Fractional part

2 13 Rem 0.125 x 2=0.25
0.25 x 2=0.5 ½ mark
2 6 1
1mk 0.5 x 2=1.0
2 3 0 0.12510 =0.0012
2 1 1
1310=11012
0 1 Therefore, 13.12510 = 1101.0012 ½ mark

v. Aparticularcomputerstoresnumbersinasingle8-bitword. Howwouldit
represent0.312510? (2marks)

0.3125 x 2 = 0.6250 0
0.6250 x 2 1.25 1
025 x 2 0.50 0

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0.5 x 2 1.00 1
= 0.01012

19( a) Explain each of the following type of operating systems (4marks)

i. Distributed
This is an operating system that manages a group of distributed computer system.
Distributed computations are carried out on more than one machine.
ii. Multi-user.
Amulti-useroperatingsystemis one that allows formultiple users to usethe same
computer at the same time and/or differenttimes. Examples include UNIX, Linux,
MAC OSand Windows Server 2003.

b)List any two types of embedded operating systems used in modern cell phones (2marks)
-Android
-Symbian
-Windows
-FreeBSD
-Minix 3
c) Mostoperatingsystemsprovide afilesystem. Mention any TWO file systems used in
windows environment. (2 marks)
FAT(file allocation table) FAT32
FAT16 NTFS(new technology file system)
(d) Define the term interactive data processing. (1mark)
In interactive data processing there is continuous dialogue between the user
and the computer. As the program executes, it keeps on prompting the user to
provide input or respond to prompts displayed on the screen.
(e) Explain why input screens are better data entry designs than entering data directly
a table. (2
marks)
- Faster way of data entry
- One record can be viewed at a time.
- Data validation is possible
- One is able to compute data.
(f) State two likely causes of data and program loss in a computer system? (2 marks)
 Computer virus corrupting data and instructions
 Uneven power supply to system components

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 Theft of data or programs
 Disk crash
Explain the meaning of the following terms as used in data security (2marks)
a. Fraud – use of computer to conceal information or cheat other people with the intention
of gaining money or information

b. Alteration – the legal charging of data or information with the intention of misinforming
authorized users or gaining

20. (a) The figure below shows an extract of an e-mail application.

State what is meant by the following (3 marks)

(a) Trash

Acts as a dust bin for your e-mail account where all deleted mails are stored before
being permanently removed from the account

(b) Spam

This is a folder in your account where all junk and suspicious mails received are
stored

(c) Inbox

This is a folder in your account where all genuine mails received are stored

b) Explain the following interactive sensory equipment used in virtual reality

(2marks)
i) Head gear
A device with tiny screens worn on the head, enable the weaver to view the virtual world.

ii) Body suit

Worn by the user, enable the wearer to explorer the virtual world

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c) Most computerized security systems make use of Biometric analysis, name three
physical features of human beings that can be considered in this analysis (3marks)
- Finger prints
- Voice recognition
- Eye / facial recognition.
d) (i) Define the term networking topology (1mark)
Refers to the arrangement of the computers, printers and other equipment
connected on the network

(ii) Distinguish between logical and physical network topologies (2marks)

Logical (signal) topology deals with the way data passes from one device to the next
in a network while physical topology refers to the physical arrangement (layout) of
devices on the network

(d) Explain the functions of the following network device (4marks)

(i) Network interface card (NIC)
Creates a physical link between the computer and the transmission media

(ii) Gateway

Provides access to a wide area network

(iii) Bridge

Device that selectively determines segment where message is to be delivered

(iv) Repeater
Receives a weak signal cleans and amplifies it for transmission over the next
position of the network

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