Computer Studies Paper 1 Questions and Answers - Form 4 End Term 2 Exams 2023

Section A (40marks)

Answer All the questions in this Section.

1.  
   1. Define the term computer virus. [2mks]
   2. Give four symptoms of a computer infected by virus. [2mks]
2. Give three factors to consider when selecting an Operating System to install in your computer. [3mks]
3. Give two advantages of DTP over a word processor. [2mks]
4. State three characteristics of a user friendly program. [3mks]
5. Give four ways of minimizing the effects of radiation from the display screen. [2mks]
6. Differentiate between soft return and hard return. [2mks]
7. State three possible causes of fire outbreak in a computer laboratory. [3mks]
8. State four ways in which a programmer can make program code easy to follow. [4mks]
9. State three reasons why it is important to define data types of field in a database correctly. [3mks]
10. State three causes of resistance to the introduction of Information and Communication Technology to the place of work by employees. [3mks]
11. List three factors to consider before choosing a storage device for backup. [3mks]
12. Explain the purpose of a Video RAM as used in computing. [2mks]
13. Explain the concept behind Environmental Protection Agency (EPA) energy star. [2mks]
14. Some devices have a combination of input and output functionality. State four such devices. [2mks]
15. Convert 374₁₀ in to BCD notation [2mks]
16.  
    1. Distinguish between interpreters and compilers [2mks]
    2. State any two activities that occur in a program compilation process. [2mks]
    3. Define the term structured programming [1mk]
    4. Use the flowchart below to answer questions that follow. Write a pseudo-code for the flowchart below. [10mks]
       
17.  
    1. What is Virtual reality? [2mks]
    2. Explain the following interactive sensory equipment used in virtual reality: [2mks]
       1. Head gear.
       2. Body suit
    3.  
       1. What is Artificial Intelligence? [2mks]
       2. State and explain three components of an experts system. [6mks]
    4. State three physical features of human beings that can be considered in Biometric analysis. [3mks]
18.  
    1. State and explain any four operating system disk management utilities. [8mks]
    2.  
       1. What is system maintenance? [2mks]
       2. Define the following terms in relation to computer software. [3mks]
          1. Free ware.
          2. Propriety
          3. Open source
       3. List any four likely causes of data and program loss in a computer system? [2mks]
19.  
    1. Distinguish between transcription and transposition types errors and give an example of each. [6mks]
    2. List four activities carried out by data processing system. [2mks]
    3. State two application areas of real time systems. [2mks]
    4.  
       1. What is a computer network topology? [2mks]
       2. Briefly explain three reasons why organizations need to network their computers. [3mks]
20.  
    1. An individual has a right to demand guarantee to privacy of personal information stored on a computer. Give three such types of information. [3mks]
    2. Describe two ways in which a computer can represent a positive and negative. [2mks]
    3. A particular computer stores numbers in a single 8-bit word. How would it represent 0.312510. [3mks]
    4. Using 8-bits binary, perform the following subtraction 710 – 410 in binary form. Leave your answer in decimal notation. [7mks]

MARKING SCHEME

Section A (40marks) Answer All the questions in this Section.  

1.  
   1. Define the term computer virus. [2mks]
      • a type of malicious software, or malware, that spreads between computers and causes damage to data and software. 
   2. Give four symptoms of a computer infected by virus. [2mks]
      • Hang ups
      • Shutting down frequently
      • Error messages
      • Quizzical messages
      • file increase and decrease
2. Give three factors to consider when selecting an Operating System to install in your computer. [3mks]
   • Processor speed
   • Purpose of the computer
   • Memory size
   • Compatibility and
   • Upgradeability
   • User needs
   • User friendliness
   • Make of the computer
3. Give two advantages of DTP over a word processor. [2mks]
   • More control over the way text is arranged and formatted
   • Bring lots of different files together on the same document
   • Easy to edit and format
   • More mediums (text, picture and graphics) to communicate ideas
4. State three characteristics of a user friendly program. [3mks]
   • Easy to update
   • Easy to install
   • Easy to navigate
   • Easy to remove
   • Easy to troubleshoot
   • Effective error handling
5. Give four ways of minimizing the effects of radiation from the display screen. [2mks]
   • Use of anti-radiation shield on the screen.
   • Use of LCD screens instead of CRT monitors.
   • Proper lighting
   • Proper screen resolution.
6. Differentiate between soft return and hard return. [2mks]
   • Soft return is the moving of the word to the beginning of the next line automatically if it does not fit in the current line while hard return is moving the cursor to the beginning of the next line by pressing the Enter / Return key on the keyboard.
7. State three possible causes of fire outbreak in a computer laboratory. [3mks]
   • Electrical faults
   • Natural causes
   • External attacks e.g. arsonists/terrorists
   • Inflammable materials
   • Accidents 
8. State four ways in which a programmer can make program code easy to follow. [4mks]
   • Using modules or short blocks of program/functions/procedures
   • Making internal documentation/comments
   • Using meaningful variable names and user words in the program;
   • Using indent to represent nested statement;
   • Using blank lines to separate blocks of code statement.
9. State three reasons why it is important to define data types of field in a database correctly. [3mks]
   • Memory use optimization when the program is loaded
   • Assist in trapping errors during data input;
   • So that appropriate computation can be performed;
   • Increase speed of processing.
10. State three causes of resistance to the introduction of Information and Communication Technology to the place of work by employees. [3mks]
    • Fear of change-people are creatures of habit, hence are afraid of change.
    • Fear of losing their jobs: By installing the computer into an organization, employees fear that they might end up losing their jobs.
    • Fear of failure-since the computer is very new in a given working environment, the people will be afraid that they might never get used to it.
    • Loss of control: The management fears that once a computer system implemented, they might lose control of the organization.
11. List three factors to consider before choosing a storage device for backup. [3mks]
    • Cost : the storage devices come in different prices
    • Availability : is the desired storage device available in the market
    • Accessibility to information stored in it : this may be sequential or direct
    • Reliability and security- one that does not easily crash
    • Storage capacity
    • Physical size and portability
    • Compatibility with the existing computer system hardware
12. Explain the purpose of a Video RAM as used in computing. [2mks]
    • VRAM chips are used to store display images for the monitor. The amount of video RAM or memory determines how fast images appear and how many colours are available. 
13. Explain the concept behind Environmental Protection Agency (EPA) energy star. [2mks]
    • EPA coerces manufacturers worldwide to comply with acceptable levels of environmental pollution and radiation.
14. Some devices have a combination of input and output functionality. State four such devices. [2mks]
    • Automated teller machine
    • Point of sale terminal (POS)
    • Voice Over Internet Protocol (VOIP)
    • Multi functioning printer (All in one) combines printer, scanner, fax and copier
    • Touch screen
15. Convert 374₁₀ in to BCD notation [2mks]
    • 3-0011 7-0111 4- 0100 hence 374=0011011101002
16.  
    1. Distinguish between interpreters and compilers [2mks]
       • Interpreters translates the source program line by line to object code by allowing the CPU to execute one line before translating the next while compilers translates the entire source program to object code at once.
    2. State any two activities that occur in a program compilation process.    [2mks]
       • Error checking
       • The source program is converted into object code.
    3. Define the term structured programming [1mk]
       • The process of breaking a program into segments or modules for easier modification and error detection.
    4. Use the flowchart below to answer questions that follow. Write a pseudo-code for the flowchart below. [10mks]
       Start
              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
        Stop
17.  
    1. What is Virtual reality? [2mks]
       • Is where a person gets psychologically immersed in an artificial environment generated by a computer system.
    2. Explain the following interactive sensory equipment used in virtual reality: [2mks]
       1. Head gear.
          • Channels images and sounds from the source to the eyes and ears of the wearer hence producing a 3-D effect in the virtual world.
       2. Body suit
          • Made of conductor wires that sense body movement and relay data into the virtual reality system.
    3.  
       1. What is Artificial Intelligence? [2mks]
          • Making computers perform tasks that could otherwise require intelligence if performed by human beings.
       2. State and explain three components of an experts system. [6mks]
          • Knowledge base - stores knowledge in form of roles as facts concerning a certain subject interest.
          • Interference engine - software which controls how knowledge is searched and accessed from the knowledge base.
          • User interference - enables the user to interact with the system.
    4. Physical features of human beings that can be considered in Bio metric analysis.    [3mks]
       • Eyes pattern
       • Finger prints
       • Voice
18.  
    1. State and explain any four operating system disk management utilities. [8mks]
       • Formatting – preparing new disk for use by printing sectors, tracks on the surface of the disk.
       • Scanning- Helps the user to check and repair minor drive problems such as lost storage locations.
       • Defragmenting a disk – consolidating fragments on a disk so that each file occupies a single, contiguous space on the drive.
       • Compressing- Reducing the amount of space the files occupies on a drive.
       • Backing up of data – enables users to create copies of data and programs.
       • Partitioning – Process of dividing large physical disk into 2 or more partitions called logical drives.
    2.  
       1. What is system maintenance?                                        [2mks]
          • Adjustments and enhancement of requirements or correction of errors after the system has been implemented.
       2. Define the following terms in relation to computer software. [3mks]
          1. Free ware.
             • Software products that are freely made available to the use.
          2. Propriety
             • Those are software whose source code is hidden for users.
          3. Open source
             • These are software whose source code is available to the user and are encouraged to modify, distribute and use.
       3. List any four likely causes of data and program loss in a computer system?    [2mks]                                         
          • Viruses
          • Hardware fault
          • Theft
          • Network breakdown.
          • Program failure.
          • Vandalism
          • Unstable power.
19.  
    1. Distinguish between transcription and transposition types errors and give an example of each. [6mks]
       • A transcription error is a specific type of data entry error that is commonly made by human operators or by optical character recognition (OCR) programs e.g. Name: Stamley (wrong) instead of Stanley(correct)
       • Transposition error is an error caused by reversing two or more digits of an amount while posting transactions. These are almost always human in origin. An example is Zip code: 57429 (wrong) instead of 54729 (correct)
    2. List four activities carried out by data processing system. [2mks]
       • Data collection
       • Data input
       • Processing
       • Output
    3. State two application areas of real time systems. [2mks]
       • Booking and reservations e.g. hotel, car, bus, air ticket
       • Space explorations
       • Intensive care units (hospital) ICU
       • Chemical plants/nuclear
       • Military security
       • Banking e.g. ATM
    4.  
       1. What is a computer network topology? [2mks]
          • Arrangement of computers on a network.
       2. Briefly explain three reasons why organizations need to network their computers. [3mks]
          • Sharing of information and other resources like printers, internet
          • Fault tolerance-it is safer to have several copies/services of work spread in a network.
          • Economy of scale-cheaper to have a network than a centralized system
          • Communication e.g. email, chatting
          • Scalability, it is cheaper to add computers on a network than to do an upgrade 
20.  
    1. An individual has a right to demand guarantee to privacy of personal information stored on a computer. Give three such types of information. [3mks]
       • Bank accounts records
       • Income tax records
       • Medical records
       • Legal records
       • Bio-data
       • Property records
    2. Describe two ways in which a computer can represent a positive and negative. [2mks]
       • In binary one bit usually the most significant or leading bit is used to indicate either positive or negative and store the unsigned binary representation of the magnitude in the remaining bits.
       • Signed magnitude
       • Using the twos complement
       • Using the ones complement
    3. A particular computer stores numbers in a single 8-bit word. How would it represent 0.312510. [3mks]
       • Answer
         0.3125 × 2 = 0.6250 - 0
         0.6250 × 2 = 1.2500 - 1
         1.2500 × 2 = 0.5000 - 0
         0.5000 × 2 = 1.0000 - 1
         Therefore 0.3125 => 0.0101₂
                                        ⇒ 0000.0101₂
    4. Using 8-bits binary, perform the following subtraction 710 – 410 in binary form. Leave your answer in decimal notation. [7mks]
       Solution
       Convert 4₁₀ to binary equivalent ie. 00000100₂
       One’s complement of 00000100₂  is 11111011₂
       Two’s complement of 11111011₂ + 1 = 11111100₂
       Add the 2’c to the binary equivalent of 7₁₀
       11111100
       00000111   (1)00000011₂
                          Ignore the overflow
                             00000111₂