Computer Studies Paper 1 Questions and Answers - Nginda Girls Mock Examination 2023

INSTRUCTIONS

Answer all questions in section A
In section B, answer question 16(compulsory) and any other three questions
Candidates should answer the questions in English.

QUESTIONS

SECTION A (40 Marks)
Answer all questions in this section

State three precautions that should be taken to prevent against electrical fire in the computer laboratory (3 marks)
Identify the most appropriate input device suitable for each of the following tasks:
1. Graphic designs and architectural drawing (1 mark)
2. Data input by a person with impaired hands (1 mark)
Sharon has noticed that her stand-alone computer has become unusually slow and hanging frequently. Since she cannot figure out the problem with the computer, she decided to format the hard disk.
1. State two data recovery measures she has to take before formatting the hard disk (2 marks)
2. State two corrective measures she should have taken before resorting to formatting the hard disk
  (2 marks)
The capacity of a computer’s RAM is 4GB
1. State one function of the RAM in the computer (1 mark)
2. Calculate the number of nibbles the memory can support if another RAM of 512MB RAM was added. (3 marks)
The independent Electoral and Boundaries Commission (IEBC) has decided to transmit election results from the constituency level to the headquarters in Nairobi through the internet. Explain two data security threats that are likely to be faced during this transmission. (4 marks)
The icons below represent commands used in a DTP package to manipulate graphics.

State the use of each of the icons labeled Figure A and Figure B (2 marks)
Explain the importance of each of the following in word processing
1. tab stops (2 marks)
2. word wrap (2 marks)
State the use of each of the following symbols in a system flowchart:
1. (1 mark)
2. (1 mark)
State two ways in which power failure is a threat to data security (2 marks)
Pesa Tele Company has realized that someone is illegally gaining access to their data in their computer networks. Name two computer professionals that the company should consult and their roles. (2 marks)
State two factors that determine the cost of an operating system (2 marks)
The examination processing system of Mamboleo high school requires entry of students’ monthly CAT marks at the end of each month. At the end of the term, the system generates a student’s termly report form.
1. Name this type of data processing mode (1 mark)
2. State two advantages of this data processing approach (2 marks)
An organization has offices in Nairobi and Kampala. The management intends to network the computers in these offices. State two factors that they need to consider when choosing a physical network topology to use. (2 marks)
Apart from sending and receiving mails, state other two functions of an email. (2 marks)
Distinguish between an index key and a primary key field as used in databases (2 marks)

SECTION B (60 Marks)
Answer question 16 (Compulsory) and any other three questions

1. Using a suitable example, explain the term mnemonics as used in programming (2 marks)
2. An interpreter is a programming language translator that converts high level languages to machine code. State three characteristics of an interpreter (3 marks)
3. The figure below shows a flowchart. Use it to answer the questions that follow:
  1. Determine all the outputs of the flowchart if the input is the number three. (3 marks)
  2. Explain what happens if the number zero is input. (1 mark)
  3. Write a pseudocode for the flowchart above (6 marks)
1. With an aid of a diagram, describe time sharing mode as used in data processing. (4 marks)
2. Explain the function of each of the following in system documentation:
  1. User Manual (2 marks)
  2. Invalid data (2 marks)
3. State two functions that are specific to networking operating systems (2 marks)
4. Mwanzo mpya holding is a company that deals with selling of computers and computer parts. State three benefits of advertising their business through the internet. (3 marks)
5. Distinguish between the integrated software and software suite (2 marks)

Perform the binary arithmetic
111.01 + 1011.111 – 101.011
And convert the answer to decimal notation (4 marks)
Using two’s complements and 8 bit notation, subtract 1110 from 810 leaving your answer in binary notation (5 marks)

The figure below is an extract of a spreadsheet showing what students had targeted to score and the actual score in a computer remedial class.

	A	B	C	D
1	NAME	TARGET SCORE	ACTUAL SCORE	PERFORMANCE FACTOR
2	Abdi	40	45
3	Alex	30	65
4	Ben	50	60
5	Betty	30	20
6	Bena	45	45
7	Sheila	70	60

A performance factor is obtained by subtracting the target score from the actual score and dividing the difference by the target score.
Using cell references, write a formula that would be entered in cell

D4 to compute the performance factor (2 marks)
E2 to display the statement ‘More remedials’ if the performance factor is less than zero, ‘Exempted’ if the factor is greater than zero and ‘optional remedials’ if otherwise. (4 marks)

1. Kenya Wildlife Service (KWS) is a government agency whose part of their responsibility is to conserve wildlife. State three ways they can use ICT to achieve their goal. (3 marks)
2. State the role of each of the following data communication devices:
  1. Gateway (1 mark)
  2. Brouter (1 mark)
  3. Codec (1 mark)
3. Explain two circumstances under which phased changeover strategy would be preferred when implementing a new system. (4 marks)
4. State three reasons why the fibre optic cable has become a very popular data communication media in most organizations today (3 marks)
5. A local bank had its electronic money transfer system attacked by a computer criminal. In their meeting over the matter, the Board of Directors instructed the CEO not to report the matter to the law enforcement agencies but to deal with it internally. State two reasons why the board of directors took such a decision. (2 marks)
1. An architectural firm uses a computer system for designing building plans. State three advantages of using CAD software instead of DTP software to perform this function. (3 marks)
2. State three reasons why it is necessary to create table relationships during database design (3marks)
3. Explain two circumstances under which the use of robots may be preferred in manufacturing industries (4 marks)
4. The growth of the internet has led to the rise of many social networking sites. State three negative impacts of these social networking services offered over the internet. (3 marks)
5. A student was advised to use ergonomic keyboard while typing his project documentation. State two health problems that can be solved when the advice is taken. (2 marks)

MARKING SCHEME

SECTION A (40 marks)

RESPONSES

MARKS

Avoid overloading power sockets
Ensure all cables are properly insulated
Use cables and sockets of proper power ratings (First 3 × 1)

Graphic tablet/Digitizer

Voice input

- Back up her data in an external storage device
- Have unformatted utility program e.g. data scavenger ( First 2 × 1)

Increase the RAM capacity
- Use an antivirus program to scan the computer for viruses
- Defragment the hard disk ( First 2 × 1)

Stores data and instruction that are awaiting processing
Store immediate results of processing
Stores instructions that are being processed by the CPU ( First 2 × 1)

512 MB = 512 000 000 bytes

4GB = 4 000 000 000 bytes ; Total RAM capacity = 4 512 000 000 bytes

1 byte = 8 bits

4512 000 000 bytes = ? bits = 36096000000 bits

1 nibble = 4 bits

? nibbles = 36096000000 bits ; 36096000000 ÷ 4 = 9 024 000 000 nibbles

Unauthorized access through hacking, tapping, eavesdropping or cracking
Computer viruses which may delete/ amend/corrupt files on transit
Power failure which may lead to delays, loss of unsaved data etc.( First 2 × 1)

Figure A – for text wrapping/ placing image behind text

Figure B – for cropping/hiding unwanted parts of an image/trimming/cutting

Tab stops –it indicates how far to indent text or where to begin a column of text
Word wrap – process by which a word which comes at the end of a line is automatically moved onto a new line in order to keep the text within the margins.

it is used to show data input
used to connect segments of the flowchart that flow to the next page

It may lead to loss of unsaved data
It may lead to crashing of the hard disk ( First 2 × 1)

10.

Data security analyst - identify and fix data security loopholes
Network Administrator – enforce security measures on the network

( First 2 × 1)

11.

Its portability
Its authenticity
The number users it can support
Its user friendliness/user interface (First 2 × 1)

12.

Batch processing / electronic data processing
It is cheap/cost effective

- It is simple to develop ( First 2 × 1)

13.

Initial and maintenance cost
Expandability of the topology – how easy is to expand
Type of transmission media required
Type of networking devices required (First 2 × 1)

14.

Online meetings e.g. through chatting
Online data back up
Telephone messaging

15.

An index key is a field that is used to speed up access of data in a database while a primary key is a field that uniquely indentifies each record in a database

SECTION B (60 Marks)

16. a)

Mnemonics are symbolic operation codes /shortened two or three letter words that used in writing programs in assembly language e.g. SUB AX, 20 (subtract 20 from the value in register AX)

Award 1 mark for correct explanation and 1 mark for suitable example

Translates source code one line at a time
Does not save the object code in memory
It is slow in execution (First 3 × 1)

c) i)

1^st iteration

2^nd iteration

3^rd iteration

Number = 3

Product = 1

Value = 3

Product = value * product

= 3 * 1 = 3

Value = value – 1

3 – 1 = 2

Is value = 0? NO

Product= 3

Value = 2

Product = value * product

= 2 * 3 = 6

Value = value – 1

2 – 1 = 1

Is value = 0? NO

Product= 6

Value = 1

Product = value * product

= 1 * 6 = 6

Value = value – 1

1– 1 = 0

Is value = 0? YES

OUTPUT Number is 3

Product is 6

Award 1 mark for each correct iteration (3 × 1)

ii)

The loop is executed infinitely many times

iii)

Start √ ½

Input number √ ½

Product =1 √ ½

Value =number √ ½

REPEAT √ 1

Product = Value * Product √ ½

Value = Value- 1 √ ½

UNTIL Value = 0 √ 1

Output number, product √ ½

Stop √ ½

Input

17. a)

This is a processing mode where many users have access to a centralized computer apparently at the same time. Each user is allocated a time slice for accessing the CPU. A user whose task requires more time than what is allocated is send back to the queue. For example, four users are apportioned equal time slice in each round until they are done.

User 1

Time = t₁

User 2

Time = t₂

User 3

Time = t₄

User 4

Time = t₄

Output

CPU

Incomplete Job back to queue

Helps the user to learn how to use the system with minimal guidance
This is data that is out of the range. It is data that the program should not accept it. It is used to test whether the system is giving the desired output/ working as intended.

Implementing network security features
Provides access to network resources
Keep a log of all people who have used the network
Support network services such as network card drivers and protocols
Enable nodes to communicate with each other (First 2×1)

There is wider coverage i.e. will be able to reach more people
Feedback from viewers/visitors can be received instantly
Service is available 24/7 thus convenient to use
The cost is low (First 3×1)

Integrated software refers to a single program that contains many different applications while software suite refers to related software that is bundled together and sold as a package

18. a)

111.01 10011.001

1011.111 -101.011

10011.001 1101.110

Convert 1101.011 to decimal

1	1	0	1	.	0	1	1
2³	2²	2¹	2⁰	.	2^-1	2^-2	2^-3
8	4	2	1	.	0.5	0.25	0.125

X ₁₀ = 8 + 4 + 0 + 1 + 0 + 0.25 + 0.125

= 13.375

Convert 11₁₀ to binary 1011₂

Convert 8₁₀ to binary 1000₂

00001000₂ - 00001011₂ ones complements of 00001011 11110100

Twos complements 11110100 +1 11110101

00001000 + 11110101 = 11111101

Deny one mark if 8 bit notation is not used

=(C4 – B4)/B4

No mark if equal sign is omitted

=IF( D2 < 0, “More remedials”, IF(D2>0, “Exempted”, “Optional remedials”))
=IF( D2 < 0, “More remedials”, IF(D2>0, “Exempted”, IF(D2 = 0, “Optional remedial”)))

19. a)

Tracking of animals using GPS/CCTV
Dissemination of information/ awareness on the need and ways of wildlife conservation
Source of knowledge on wildlife conservation matters
Seeking for funding from sponsors (First 3 × 1)

Gate way – used to connect/ enable communication between two systems that do not use the same network architecture and environment
Brouter – a device that combines the functionality of a bridge and a router
Codec – converts data from one form to another e.g. from analog to digital an vice versa

When changing over systems that are massive and complex since it is done in phases the entire system is overhauled once the analyst is satisfied that each phase is working well.
For critical systems because if a phase fails the effects are not devastating

It has a high bandwidth
It suffers less attenuation
They transmit data very fast
It is not easy to tap information from the fibre optic cable
They are much lighter than the other types of cables
They can be used in a highly flammable environment since they don’t carry electrical signals (First 3 × 1)

The law enforcement agencies may lack adequate capacity to get the culprits
There are no adequate provisions in the law to handle such criminals
Fear that it could be an inside job and thus could de market them (First 2 × 1)

20. a)

They enable designers to create 3-D objects that can be viewed from different angles
They have superior facilities such as color palette, library of symbols and forms, drawing tools etc.
They keep track of related designs such that when a change is made on one design it is automatically reflected on the rest (First 3 × 1)

To enable querying of multiple tables
To reduce data redundancy/unnecessary duplication of data
Reduces data inconsistencies in a database (First 3 × 1)

·When dealing with repetitive tasks which might cause boredom to human beings
When processes are being performed under hazardous environments for human beings
When consistent and high standard products are needed since robots operate on GIGO principle (First 2 × 2)