COMPUTER STUDIES PAPER 1 - 2019 KCSE KASSU JOINT MOCK EXAMS (QUESTIONS AND ANSWERS)

SECTION A ( 40 MARKS)
Attempt all questions in this section.

1. List down four features of a user friendly program       (2Marks)
   1. Define the term file organization.        (1Mark)
   2. Explain two methods of file access.      (2Marks)
2. List four number systems that the design and organization of a computer may depend on. (2Marks)
3. Explain the meaning of the following terms as used in computer communication (2Marks)
   
   1. Modulation
   2. Remote communication
4. Using one’s complement, calculate 11011₂-111₂ and leave your answer in binary notation. (3Marks)
5. List three types of computers that are classified according to the type of signal they use when functioning. (3Marks)
6. In relation to DTP, explain the meaning of (2Marks)
   1. Pasteboard
   2. Master page
7. Give two main functions of a primary key in a database.    (1Mark)
8. Differentiate between LPT ports and COM ports as used in Computer Printers.    (2Marks)
   1. Define the term Cyber space.                                                                                           (1Mark)
   2. Give three components of a virtual reality system and state their use.                           (3Marks)
9. Highlight any two ways in which computers are used as industrial systems. (2Marks)
   1. Indicate the type of cell reference depicted by the following.                                        (3Marks)
      1. $H$5
      2. H $ 5
      3. H 5
   2. Give three uses of spreadsheets in a government office concerned with carrying out national census       (3Marks)
10. The Chairman IEBC has called upon a System Analyst to implement an electronic voting system. He intends to use voter’s fingerprints, Identity cards and voter’s cards as security measures to ensure free and fair elections. Recommend with reasons four input devices that they should use/buy. (4Marks)                                                                                                                                                                                                                                           
11. State any four security control measures that can be taken to detect and protect computer systems against computer crimes.      (2Marks)
12. List four features of Electronic mail          (2Marks)

SECTION B ( 60 MARKS)
Answer questions 16 and any other three questions from this section

16.  
    1. Define the following terms as used in programming.    (2Marks)
       1. Assembler
       2. Monolithic program
    2. With the aid of flowchart segments, highlight two differences between the REPEAT….UNTIL and WHILE…..DO statement structures.    (4Marks)
    3. Give the name and use of the flowchart symbol below.    (1Mark)
                                          
       1. Name 
       2. Use
    4. State any two functions of programming language translators                             (1 mark)
    5. Draw a flowchart that can be used to create a program which accept a numerical pin, if the pin is equal to 0721, the program outputs , correct pin and asks for personal pin, if the pin is 1737, the output is “Admitted to UON,” 1738, the output is “Admitted to MARKU”, 1739 the output is “Admitted to KEMU” after outputting the secret message the program stops.  (7 Marks)

17.  
    1. The following diagram shows the stages of developing an information system.
       
       
       1. List any four methods that can be used to achieve the second stage in above.      (2Marks)
       2. List any four areas that have to be designed at the fourth stage.      (4Marks)
       3. Give one likely consequence of a project that does not stick to its schedule           (2Marks)
    2. Explain the meaning of the following system characteristics.                                        (4Marks)
       1. Entropy
       2. Controls
    3. State the three functions of an information system.      (3Marks)
18.  
    1. Distinguish between the following pairs of word processing terms
       1. A widow and an orphan     (2 marks)
       2. Footnote and end notes     (2 marks)
    2. Study the Microsoft Word table below and answer question which follow
       

       Item		Quantity	Price(sh)	Total
       Bread		2	33.0	66.0
       Milk(litres)		4	30.0
       Potatoes		1	75.0
       Others	Cooking fat(kg)	1	180.0	A
       	Salt(250 g)	1	15.0	15.0
       Total				B

       
       
       1. Supply a formula or function in Cell with letter A to calculate the total amount spent on 1 kg of cooking fat    (2 marks)
       2. Supply a formula or function in cell with letter B to calculate total expenditure on all items                                                                                                
    3. The following is a spreadsheet relating to a farmer.
       

       	A	B	C
       1	Crop	Amount
       2	Maize	150
       3	Bean	300
       4	Cashew nuts	850
       5	Cabbages	1036

       
       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    (2Marks)
    4. Define the terms as used in databases   (3Marks)
       1. Attribute
       2. Relationship
       3. Dynaset
    5. List any four database models.     (2marks)
19.  
    1. State three characteristics of RAM.    (3Marks)
    2. A computer virus is malicious software which may affect the smooth running of a computer   system or carry out illegal activities in the computer.
       1. Name three types of computer viruses and state the effect of each when it gets in to a computer                  (3 marks)
       2. State any two methods to control infection of a standalone computer by virus (2 marks)                                                                                               
    3. Mr. Yugo, the Biology teacher, intends to use a multimedia system to demonstrate dissection of a frog.
       1. What is a multimedia system?  (1 mark)
       2. List four components that make a multimedia system                                                   (2 marks)
    4. State any two softcopy output devices.                                                                          (2marks)
    5. State two main ways in which secondary storage devices are classified                  (2 marks)
20.  
    1. Distinguish between guided and unguided transmission media and give one example of each.
    2. State two functions of Hubs.        (2Marks)
    3. Explain two different ways in which computers can enhance communication in Kenya today.
    4. State and explain how the benefits of technology were not effectively used during the 2007 general elections. (3Marks)
    5. Explain the difference between a data Terminal Equipment (DTE) and Data Circuit – terminating Equipment (DCE) and give examples of each.  (3Marks)

MARKING SCHEME

1. List down four features of a user friendly program
   • Error reporting and recovery
   • Good screen display
   • Validation of input
   • Comment statements
   • Indentations
   • Self- descriptive variables
   • Menu driven
   • Online help            
     first four @ ½ mk = 2 mks

2.  
   1. The systematic arrangement of files in a computer secondary memory.        (1mk)
   2.  
      1. Direct file access      
      2. Indexed
      3. Serial - indexed           
         (first 2x 1 = 2mks)

3.  
   • Hexadecimal
   • Octals                          (Each 1 mk x 4 = 4mks)
   • Decimal
   • Binary

4.  
   1. Changing of the digital data to analog data.
   2. This is the transfer of data between computers in different locations
      It is  a long- distance  data transfer  without  the use of cables

5. 1011₂ P  - 111₂P        
   00100₂P-  000₂P
   00100₂P           (4mks)

6. Digital computer
   Analog computer
   Hybrid Computer                   
   (Each 1 mk x 3 = 3mks)

7.  
   1. An area in a DTP package where work is organized before placing it on the printable area.   (1mk)
   2. pages used for general organization and format of a publication                   (1mk)

8. Give two main functions of a primary key in a database.
   • Used for relating records of similar characteristics within a database                        (1mk)
   • Prevents user from null entries
   • Creates an index to speed up searches
   • Controls redundancy                                                    first two @ ½ mk = 1 mks

9. Differentiate between LPT (parallel) ports and COM (serial) ports as used in Computer Printers.  
   • Serial ports have 9 pins, while parallel ports have holes for 9 or 25 pins
   • Parallel cables transmit several bits of data simultaneously, while serial cables transmit One bit at a time
   • Serial cables are slower than parallel cable
   • Serial cables allow for 2 ways communication (i.e. communication to and from the computer and the device connected to it) while parallel cables usually offer 1- way communication.

10.  
    1. A situation / condition in which a person becomes psychological immersed in An artificial environment generated by a computer system.     (1mk)
    2.  
       • Headgear-To channel images and sound from the source to the eyes producing a 3D effect
       • Gloves
       • Body suit-sense body movement and relay data into virtual reality system
       • Virtual reality software.  (Any three well explained points 1 x 3 = 3 mks)

11.  
    • Process control
    • CAD / CAM   (Any two well highlighted each 1 mk x 2 = 2mks)
    • Simulation.
12.  
    1. Absolute
    2. Mixed
    3.  
       1. Relative
       2. Give three uses of spreadsheets in a government office concerned with carrying out national census                                                                           
          • Tallying population size
          • Establishing demographic trends
          • Drawing  pie charts to show population share for men and women
          • Doing census budgets

13.  
    • Biometric scanner: It captures biometric details like fingerprints
    • Digital camera: captures the voters photographs
    • Keyboard: key in the voters details
    • Mouse: issue command to the computer.
      any other relevant input device  

14. State any four security control measures that can be taken to detect and protect computer systems against computer crimes
    • Installation of anti – virus 
    • Use of passwords
    • Audit trail
    • Fire wall           first four @ ½ mk = 2 mks

15. List four features of Electronic mail     
    • checking mails
    • compose message
    • send mail
    • Saving messages
    • Printing mails
    • Forwarded messages      
      first four @ ½ mk = 2 mks                                                                        

16.  
    1.  
       1. A programming language that translates an assembly language into machine language.    (1mk)
       2. This is a program that has not been broken down into smaller modules/chunks                                           
    2. In repeat – until the statements are executed before the condition is tested while in the while do the condition is tested before the statements are executed.     4 mks
       
    3.  
       1. Connectors
       2. Used to join the logical flow    (2mks)
    4. state three functions of programming language translators                    (3 marks)
       
       
       • ¾ Translate high level languages to machine languages
       • ¾ Detects errors on the source code
       • ¾ organize the storage of variables used in the computer
       • ¾ Link program with the operating system 

17.  
    1.  
       1. Study of available documents
          • Interview
          • Questionnaires    (Each 1 mk x 4 = 4mks)
          • Observation
          • Automated methods
       2. Flowcharts
          • Data flow diagrams
          • Entity relationship models
          • Structured charts
          • Decision tables/trees
       3. Give one likely consequence of a project that does not stick to its schedule        
          • it will overshoot its budget
          • It will not be concluded within the specified time 
    2. Entropy-process in which system decays/fails to meet the needs of an organization with time Controls --- system control is a method by which a system adapts to changes in the environment in order to give the expected output or perform at the expected level.(Well explained each 2 mks x 2 = 4mks)
    3.  
       • Supporting information processing
       • Help in decision making
       • Enable sharing information        (Each 1 mk x 4 = 4mks)

18.  
    1. Distinguish between the following pairs of word processing terms
       1. A widow and an orphan      (2 marks)
          A window is a heading without the appropriate body part while an orphan is the body without the heading.
       2. Footnote and end notes                                                                                      (2 marks)
          Footnotes are short text in large documents to explain, comment on, or provide references for text in a document and appear at the bottom of the page while endnotes are comments or references for text in a document, that appear at the end of a section or the document
    2. Study the Ms Word table below and answer question which follow
       

       Item		Quantity	Price(sh)	Total
       Bread		2	33.0	66.0
       Milk(litres)		4	30.0
       Potatoes		1	75.0
       Others	Cooking fat(kg)	1	180.0	A
       	Salt(250 g)	1	15.0	15.0
       Total				B

       
       
       1. Supply a formula or function in Cell with letter A to calculate the total amount spent on 1 kg of cooking fat   (2 marks)
          = product ([left])or =C5*D5
       2. Supply a formula or function in cell with letter B to calculate total expenditure on all items     (2 marks)
          =sum ([above])or =E2+E3+E4+E5
    3. The following is a spreadsheet relating to a farmer.
       1. 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                         
       2. A dynaset:  Is the result returned by a query (1  mk)
    4.  
       • Flat model
       • Related model
       • Hierarchical model                                                      (1 x 3 = 3mks)
19.  
    1.  
       • Used for holding data & instructions required immediately by the CPU
       • It is accessed directly  by the CPU
       • Provides fast access to information is accurate  & reliable
       • It is expensive per bit of memory dues to the technology involved
       • It has low/ limited storage capacity
       • It is  volatile & therefore it is used to store temporary programs & data
    2. A computer virus is malicious software which may affect the smooth running of a computer   system or carry out illegal activities in the computer.
       1. Name three types of computer viruses and state the effect of each when it gets in to a computer         (3 marks)
          - Boot sector virus which destroy booting information on the media
          - File virus which attach themselves to files
          - Hoax virus come as e-mails with attractive messages and launches themselves when mails are opened
          - Trojan horse which appear to perform useful functions but performs undesirable functions in the background
          - Worms are programs which replicates hence clogging the system memory
          (well explained first 3 @ 1 = 3mks)
       2. State any two methods to control infection of a standalone computer by virus       (First 2x1 = 2 marks)
          - Install latest version of anti-virus software and ensure that you update regularly
          - Scan any new storage media before opening their content
    3. yego, the Biology teacher, intends to use a multimedia system to demonstrate dissection of a frog.
       1. What is a multimedia system?          (1 mark)
          - It’s a system which transmit information using more than one media such as text and graphics or sound and animation
          - A combination of video, audio, text and images to provide interactive, creative and effective way of producing and communicating information.
       2. List four components that make a multimedia system         (2 marks)
          - Speakers, CD/DVD drive, Sound card and SVGA(super video graphics array)  monitor
          first four @ ½ mk = 2 mks
20. 1. Guided/bounded                                                                     unguided /unbounded
       Transmission that is directional                               Transmission that is not directional
    2. In bounded media, data signals are transmitted from the source to the destination through a restricted pathway, e.g., two open wire cables, twisted pair cables, Coaxial cables, fiber optic cables.
       Unbounded media transmits data without physical connections, e.g. microwave, satellite, radio, infrared communication.
    3. Connects computer
       Connects network
    4. Linking mobile phone in communication
       Transfer of data from one point to another
    5. Most of work done manually
       Hate message sent through mobile phone
       Poor storage of election results
       (3 well explained @ 1 = 3 mks)
    6. DTE is any device e.g. a computer workstation on a network, while a DCE ends / marks the end of physical network circuit.      (2mks)