Computer Studies Paper 1 Questions and Answers - Lanjet Mock Exams 2021/2022

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INSTRUCTIONS TO CANDIDATES:

  • This paper consists of two sections.
  • Answer all the questions in section A.
  • Answer question 16 (compulsory) and any other three questions from section B.

SECTION A (40MARKS)
Answer ALL questions in this section in the spaces provided

  1. State two practices to be observed in a computer laboratory in order to ensure the safety of the computer user (2marks)
  2. Define portability as used in software selection (1mark)
  3.  
    1. How does an operating system manage computer memory (2marks)
    2.  
      1. What is meant by disk partitioning? (1mark)
      2. State the purpose of disk partitioning (1mark)
  4.  
    1. List four stages in data processing cycle (2marks)
    2. What is meant by the following (2marks)
      1. Reference file
      2. Master file
  5.  
    1. Describe two situations in the bus transport industry where computerized systems could replace human employees. (2marks)
    2. State one role of
      1. Webmaster (1mark)
      2. Network administrator (1mark)
  6.  
    1. Give one reason why parallel cables are faster than serial cables in data transmission (1mark)
    2. State any two ways that may be used to represent a negative number in a computer. (2marks)
  7.  
    1. Distinguish between autocomplete and the autocorrect feature in word processing. (2marks)
    2. What is thesaurus? (1mark)
  8. Define the following terms as used in internet (2marks)
    1. Internet
    2. Piconet
  9. Give two reasons why a DTP is preferred over Word Processors in creation and editing of magazines (2marks)
  10. The following are symbols of some keys on the keyboard. Name the keys represented by the symbols (2marks)
    Comp LJM PP1 Q10 2122
  11. As a computer student you have been asked to assist in buying an input device. State any four factors to consider when buying input devices (4marks)
  12.  
    1. Distinguish between a workbook and a worksheet as used in spreadsheets (2marks)
    2. What is the meaning of ‘what if analysis’ with respect to spreadsheet? (1mark)
  13. Give a reason why HTML is not considered as a true programming language. (1mark)
  14. Define the following computer crimes
    1. Piracy (1mark)
    2. Industrial espionage (1mark)
  15. State the following types of relationship as used in database design (3marks)
    1.  
      Comp LJM PP1 Q15i 2122
    2.  
      Comp LJM PP1 Q15ii 2122
    3.  
      Comp LJM PP1 Q15iii 2122

SECTION B (60MARKS)
Answer question 16 (compulsory) and any other THREE questions from this section

  1.  
    1. State three advantages of low -level languages (3marks)
    2. Give two differences between a compiler and an interpreter. (2marks)
    3.  
      1. Draw a program flow chart to give out the sum and average of the first 50 odd numbers in the series: 1, 3, 5... (5marks)
      2. Write a pseudo to give out the sum and average of the first 50 odd numbers in the series: 1, 3, 5…
        (5 marks)
  2.  
    1. Use two complement to perform the following arithmetic operations
      1. 1510 -1210 (4marks)
      2. 101112- 10112 (3marks)
    2. 10112 is a ones complement binary representation of negative number using four bits work out the likely positive equivalent in base 10. (4marks)
    3. Convert the decimal fraction 10.37510 into its binary equivalent (4marks)
    4. Assuming the existence of base five, list the numbers used in the number system (1mark)
  3.  
    1. Highlight three circumstances that necessitate the development of new information systems(3marks)
    2. Describe three factors that cause system entropy (3marks)
    3. State two tools that a system analyst may use to design a system (1mark)
    4. Outline three factors that should be considered when sourcing for hardware and software resources required for a new system (3marks)
    5. Name two circumstances in which it is better to use a questionnaire than a interview for gathering information (2marks)
    6. State three reasons why users may resist the introduction of an information system in their place of work (3marks)
  4.  
    1. Explain why a computer is able to display the correct time and date when it has just be switched on.  (2marks)
    2. Discuss two types of special memories found in a Computer System. (4marks)
    3.  
      1. Define a Bus with reference to a computer system. (1mark)
      2. List two examples of buses. (2marks)
    4. Distinguish between a power cable and interface cable. (2marks)
    5. Differentiate between the different types of RAM. (4marks)
  5.  
    1. Explain how you can defend your files from the following risks.
      1. Fire in the computer laboratory (2 marks)
      2. Hackers (2 marks)
      3. Virus attacks (2 marks)
      4. Disgruntled ex-employees (2 marks)
    2. Distinguish between private and confidential data (4 marks)
    3. List three sources of computer viruses (3 marks)


MARKING SCHEME

  1. Two practices that ensure the safety of the computer user
    • All cables should be insulated
    • Cables should be laid away from user pathways.
    • Providing standard furniture
    • Use antiglare screens on CRT monitors
    • Avoid overcrowding of computers and users.
    • Adjust the display lighting.
      (First 2x1)
  2. Definition of portability as used in software selection
    • Ability of a software to be copied or installed in more than one computer.  (first 1x1)
  3.  
    1. How OS manage computer memory
      • OS manage the memory by organizing it into blocks of sizes called page frames. Task are equally divided into pieces that can fit into the frames.
      • OS swaps the tasks between the main memory and the virtual memory on the hard disk.
        (first 1x2)
    2.  
      1. What is meant by disk partitioning?
        • Process of diving a large physical disk into two or more partitions called logical drives.
          (First 1x1)
      2. Purpose of disk partitioning
        • For the purpose of installing more than one OS on the same disk.
        • For the purpose of backup on the same disk but different partitions.
          (first 1x1)
  4.  
    1. Four stages in data processing cycle
      • Data collection
      • Data input
      • Data processing
      • Data output
        (In correct sequence) (first 4x ½ )
    2.  
      1. Reference file
        • A file that contain data used for lookup purposes e.g. price list. (first 1x1)
      2. Master file
        • Contains relatively permanent data (first 1x1)
  5.  
    1.  
      • Body scanners will replace security guards by scanning travellers as they enter to detect prohibited items.
      • Online booking will replace clerks at booking offices
      • Payments using plastic cards (electronic) will replace receipt inspectors and conductors.
        (first 2x1)
    2. One role of:
      1. Webmaster
        • Develop websites for organization and individuals
        • Install web pages information
        • Maintain, update and modify information on webpages.
          (first 1x1)
      2. Network administrator
        • Controls and monitors Network resource usage
        • Sets up a computer network
        • Maintain and troubleshoot network related problems
        • Maintain and enforce network security measures.
          (first 1x1)
  6.  
    1. One reasons why parallel cables are faster than serial cables in data transmission
      • Parallel cables transmit many bits of data simultaneously using set of conductors while serial cables transmit only one bit at time. (first 1x1)
    2. Two ways that may be used to represent a negative number in a number
      • Ones complements
      • Twos complement
      • Prefixing an extra sign bit
        (first 2x1)
  7.  
    1. Distinguish between autocomplete and the autocorrect feature
      • Autocomplete is a feature that automatically displays a complete word when the user types the first few characters.
      • Autocorrect is a feature that automatically detects wrongly capitalized or spelt word and replaces it with the correct one.
        (first 1x2)
    2. What is thesaurus?
      • A tool that helps the user find words or phrases with similar meaning or opposite meaning to the one selected (first 1x1)
  8. Definition of:
    1. Internet
      • Interconnection of computer networks globally to facilitate flow of information world widely. (first 1x1)
    2. Piconet 
      • A network of bluetooth enabled devices.
      • A device / software that enable Bluetooth – enabled devices to communicate. (first 1x1)
  9. Reasons why DTP is preferred over word processors
    • Items can be edited independently since every item on a page is contained in a frame.
    • Frames need not to flow in logical sequence e.g. a story on pages I can be continued on page 5.
    • DTP has a wide range of templates that can be used to create a document first
    • Master pages are used to set a common layout which may be repeated on several pages. (first 2x1)
  10. Symbols of some keyboard keys:
    Comp LJM PP1 Ans10 2122
    4 x ½ = 2 mks
  11. Factors to consider when buying input devices
    • Initial cost of the input device
    • Volume of data to be input (Speed of the device)
    • Reliability of the device
    • Mode of operation
    • Appropriateness of the device.
      (first 4x1)
  12.  
    1. Distinguish between workbook and a worksheet
      1.  
        • Workbook – An excel file that consists of several worksheet
        • Workbook – a group of worksheets
      2. Worksheet – a work area made up of rows and columns into which data is entered. (1x2)
    2. Meaning of “what if analysis”
      • A feature used to predict / forecast an outcome if a value used in a formula or function are changed. (1x1)
  13. Reason why HTML is not considered as a true programming language
    • HTML does not have declaration part and control structures (first 1x1)
  14. Definition of:
    1. Piracy – Illegal copying of copyrighted software. (First 1x1)
    2. Industrial espionage - Involves spying on a competitor to get information that can be used to cripple the competitor. (First 1x1)
  15. Types of relationships as used in database design
    Comps LJM PP1 Ans 15 2122
    3 x 1 = 3 marks
  16.  
    1.  
      • The CPU can easily understand low – level languages without or with little translation
      • The program instructions can be executed by the processor much faster as complex instructing are already broken down into smaller simpler ones .
      • They have a close control over the hardware, are highly efficient and allow direct control of each operation
      • They require less memory space
      • They are stable i.e. do not crash once written
      • Not commonly used, hence can be used to code secret programs (Each 3 correct @ 1 mk x 3= 3 mks)
    2.  
       Interpreters   Compilers 
      Translates the source program one instruction at a time.  Translates the entire source code at once before execution
      Translates the program each time it runs hence slower than the compiler Executes faster than the interpreter since the object code can be stored and retrieved when required 
      Interpreted object code occupies less space than the compiled one. Since compiled object files are larger than the interpreted ones, they thus occupy large space. 
    3.   

      1. Comp LJM PP1 Ans16c 2122
      2. PSEUDO CODE
        Begin
        Set C= 1
        Sum = 0
        N= 1
        Repeat
        Sum = Sum+ N
        N= N + 2
        C= C + 1
        Until c= 50
        Avg= Sum/ C
        Print Sum, Avg
        End
  17.  
    1.  
      1. 1510
                 = 11112
        1210 = 11002 ✔1 mk
        Ones complement of = 11002 = 00112 ✔ (1mk)
        2c5 of 0011 = 0011+ 1 = 0100 ✔mk
        Therefore:
                            11112
                         + 01002
        Overflow bit 10112
                             0011 +
                         = 00112 ✔ 1 mk
      2. 101112 - 10112
        Ones complement of 010112 = 101002✔ 1 mk
        2c5 = 10101✔ 1
        Therefore  10111
                            10101✔ 1
                        1 01100
                            01100 ✔ 1
    2. 1011 → -ve number
      0100 → +ve number ✔ 1
      = 1 x 22 = 4
         ✔1 ✔1 ✔1
    3. Whole numbers
      Comp LJM PP1 Ans17c 2122
      Combine the two
        = 10102 + 0.0112 ✔1mk
        = 1010.0112 ✔1 mk
    4. Base five numbers
      0, 2, 3, 4 ✔ 1mk
  18.  
    1.  
      • New opportunities – new technology/ a chance to improve services.
      • Problems – undesired situations that prevent the organization from meeting its goals.
      • Directives from the management or government. (First 3x1)
    2.  
      • Improvement in technology
      • Change in user requirement
      • New management policies     (3x1)
    3.  
      • Flowcharts
      • Pseudcodes
      • Data flow diagrams        (First 2x½ )
      • Quality
      • Price
      • Service after the sale
    4. Advantages of questionnaire over interview
      • Where sincere responses are required
      • Where responses are not urgent
      • When the area to be covered is large (geographically) and respondents are scattered    (First 2x1)
    5. Reasons why users may resist introduction of information system in place of work
      • Fear of losing job
      • Fear of being displaced by computer literate people
      • Fear of side effects on their health.     (First 3x1)
  19.  
    1. Explain why a computer is able to display the correct time and date when it has just be switched on. (2mks)
      • Because it is set and stored in a special memory known as the complementary metal – oxide semiconductor (cmos) chip which is powered by cmos battery
    2. Discuss two types of special memories found in computer system. (4 mks)
      1. Cache – Fast type of RAM found in the processor.
      2. Buffers – Special memories found in the input / output devices.
      3. Register - Hold one piece of date at a time and are found in the ALU
    3.  
      1. Define a bus with reference to a computer system. (1 mk)
        • Bus – This are electronic pathways or links
      2. List two examples of buses (2 mks)
        • Address bus 
        • Data bus
        • Control bus
    4. Distinguish between a power cable and interface cable. (2 mks)
      • A power cable is used to transmit data from the source (socket) to the computer while interface cables are special cables used to connect peripheral cables to the system unit.
    5. Differentiate between the different types of RAM. (4 mks)
      • Static RAM – is a fast type of RAM located inside the microprocessor
      • Dynamic RAM – is a relatively slow type of RAM. It has the tendency for the stored charge to leak a way even with constant power supply hence requires periodic recharging.
  20.  
    1.  
      1.  
        • Avoid smoke
        • Keep flammable substances away
        • Have fire exists and fire extinguishers
      2.  
        • Use passwords
        • Change passwords frequently
        • Keep password safe
      3.  
        • Install latest updated antivirus program
        • Disable floppy disk drives
        • Scan storage devices
      4. Encrypt data
    2. Data that belongs to particular person that requires permission to be accessed
      Confidential data is that which is held by a country or an organisation about people and must be accessed by only authorised persons.
    3.  
      • Downloads
      • Pirated software
      • Fake games
      • Infected software
      • E – mail attachments
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