WAEC SSCE - Computer Studies - 2017

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The table above represents the Truth Table for the NAND (Not AND) logic gate. In digital electronics, a NAND gate is a logic gate which produces a high output (1) only when all inputs are low (0). It operates like an AND gate, followed by a NOT gate. The output of the NAND gate is the inverse of the AND gate. The NAND gate is widely used in digital circuits as it is a universal gate, meaning that any other logic gate can be realized using NAND gates only.

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The features of a web browser are the tools, functions or options that enable users to interact with web pages and navigate the internet. The title bar, address bar and menu bar are some of the common features of web browsers. However, the formula bar is not a feature of web browsers. The formula bar is a feature of spreadsheet applications like Microsoft Excel, and it is used to enter and view formulas or functions used in calculating data. Therefore, option B (Formula bar) is the correct answer.

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The method of accessing a file determines the order in which data is read or written to a file. "Circular," "random," "serial," and "sequential" are all valid methods of accessing a file. Therefore, none of the options listed is not a method of accessing a file.

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The view used to create database objects in Microsoft Access is the Design view. This view allows the user to create and modify tables, forms, queries, and reports by specifying their structures and properties. In the Design view, the user can define the fields or columns of a table, set their data types, specify primary keys, and establish relationships between tables. The Design view provides a graphical interface that allows the user to drag and drop fields, add new fields, and modify existing ones. It also allows the user to set validation rules, input masks, default values, and other properties for the fields. Overall, the Design view is a powerful tool that enables the user to create and customize database objects to meet specific requirements.

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The correct answer is "software". Software is a set of programs, routines, and procedures that are used to operate the computer hardware. It is the non-tangible part of a computer system that provides instructions to the hardware on what tasks to perform. There are different types of software including system software (such as operating systems and device drivers) and application software (such as word processors, spreadsheets, and multimedia players). Firmware is a type of software that is stored in non-volatile memory and is responsible for controlling low-level operations of hardware components. Shareware is a type of software that is distributed for free initially but requires payment after a trial period. Utility software is a type of software that provides specific tools to perform tasks such as system optimization, data backup, and virus scanning.

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The input device that is best used to capture fingerprints is option III, a fingerprint scanner. A fingerprint scanner is a device that captures the unique pattern of ridges and valleys on the surface of a person's fingertip. It works by illuminating the finger with a light source and capturing the reflection of the light through a sensor that reads the pattern of the ridges and valleys. Fingerprint scanners are widely used for security purposes, such as in biometric authentication systems for access control or identity verification. They are very accurate and reliable, and the captured fingerprints can be stored in a database for later comparison and identification. In contrast, the other options listed (I, II, and IV) are not specifically designed to capture fingerprints. Option I, a keyboard, is used for typing text, option II, a mouse, is used for pointing and clicking on a computer screen, and option IV, a microphone, is used for recording sound. While these input devices may have some limited capacity to capture fingerprints (e.g. if someone types with dirty fingers), they are not optimized for this purpose and are not as reliable or accurate as a dedicated fingerprint scanner.

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A primary key is a field in a database table that is used to uniquely identify each record in the table. It must have a unique value for each record and cannot be null or empty. The primary key is used to link related tables in a database and is essential for maintaining data integrity and accuracy.

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The copyright law is used to protect intellectual property. Intellectual property refers to the creations of the human mind, such as inventions, literary and artistic works, designs, symbols, and names. Copyright law gives the creator of a work the exclusive right to use and distribute their work, which can include things like books, music, and movies. It helps ensure that creators are compensated for their work and that others cannot use or profit from their creations without permission.

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The ICT security policy that is not good is "Re-use of old password". Reusing old passwords is not a good practice because it increases the chances of someone accessing your accounts without your permission. Hackers can obtain your old password from a previous breach and use it to gain access to your other accounts. It is essential to use strong and unique passwords for each account and not reuse old passwords. Using a password manager can help you generate and store complex passwords for each account.

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The given table shows the decimal code and ASCII code for characters N, O, and T. The cell labelled I in the table represents the ASCII code for character "O", which is 1001111 in binary and 79 in decimal. The ASCII code is a standard code used to represent characters in computers and communication devices. In this case, the ASCII code for character "O" is represented in binary as 1001111 and in decimal as 79. Therefore, the correct answer is option D, which is 79.

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The correct answer is "II, I and ll". The first step is to go to the homepage of the email service provider. The second step is to click on the "create new account" button. This will take you to the account creation page where you will be prompted to enter your personal information such as name, date of birth, and contact information. Finally, you will create a username and password and click on the "create my account" button to complete the process.

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The statement that can be used for looping in BASIC is "FOR ... NEXT". The FOR loop is used to execute a set of statements a specified number of times, while the NEXT statement is used to terminate the FOR loop. The general format for the FOR loop is:

FOR variable = start_value TO end_value [STEP step_value]
    [statements]
NEXT variable

The variable is set to the start value, and the loop executes until it reaches the end value, incrementing by the step value (if provided) each time. The statements inside the loop are executed for each iteration of the loop. The NEXT statement is used to indicate the end of the loop and to specify the variable that is being incremented.

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Lotus 1-2-3 and MS Access are spreadsheet and database management software, respectively, and Opera is a web browser. These software cannot be used to write a high-level program source code. Text Editor, on the other hand, is a simple software application that allows users to create and edit plain text files. It can be used to write source code for a high-level programming language such as Python, Java, or C++. Therefore, Text Editor is the correct option for writing a high-level program source code.

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The census machine was invented by Herman Hollerith. Herman Hollerith was an American inventor who developed a punched card tabulating machine based on the Jacquard loom principles. He invented the machine in the late 19th century to help process and analyze data from the US census, which had grown too large and complex to be handled manually. The machine used punched cards to store and process data, and it was able to process information much faster than human operators. This invention laid the foundation for modern data processing and is considered a major milestone in the history of computing.

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Without the table or any additional information provided, it is not possible to determine which cell is labelled "ll" and what value it represents. Please provide more context or information to help answer your question.

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The keyword DIM in the QBASIC statement stands for "dimension". In programming, the DIM statement is used to declare the size of an array, which is a collection of variables of the same data type. In this case, the array is called DEPOSIT and has two dimensions: one dimension has a size of 2, and the other dimension has a size of 10. This means that the array can hold up to 20 values. So, the keyword DIM is used to specify the dimensions of an array in QBASIC, allowing the program to allocate the necessary amount of memory to store the data.

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The correct answer is "requires regular supply of power". A computerized file system is an electronic system that stores and organizes data on a computer. One of the key requirements for a computerized file system to function properly is a regular supply of power. Without power, the computer and its file system cannot operate, and access to the files is limited. The other options listed do not directly relate to limiting access to a computerized file system. For example, the amount of space occupied by the file system does not necessarily limit access, and a highly efficient processing system may actually enhance access to information.

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Bookmarks are used to quickly jump to a specific location in a document. When working on a large document, it may be helpful to bookmark certain pages or sections so that you can easily return to them later without having to scroll through the entire document. By setting a bookmark, you can quickly jump to that specific location by clicking on the bookmark option, which saves you time and effort. Therefore, the correct option is: "quickly jump to a specific location in a document".

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The expression DEPOSIT(1,10) stands for an array with 10 elements. The first number in the parentheses represents the starting index of the array, which in this case is 1. The second number represents the ending index of the array, which in this case is 10. Therefore, there are 10 elements in the array, with index numbers ranging from 1 to 10.

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Soft boot is initiated by pressing Ctrl + Alt + Del keys simultaneously. This key combination sends a signal to the computer's operating system to restart the system, without shutting down the computer entirely. Soft booting allows the computer to reboot quickly and is often used when troubleshooting software or hardware issues that require a system restart.

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A dedicated channel must be established between two parties through the period of communication. In a circuit switching communication system, a dedicated physical communication path is established between the sender and the receiver for the duration of the communication session. During this time, the entire capacity of the channel is reserved for the transmission of the message, which results in a highly reliable and efficient mode of communication. However, this method of communication is not ideal for real-time communication, as the dedicated channel may remain idle during periods of silence, resulting in inefficient use of bandwidth. Therefore, this statement is false. In contrast, packet switching is more suited for real-time communication and involves breaking the message into packets that are transmitted independently and reassembled at the receiver.

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A computer that requests the services of another computer on a network is called a "client". In a client-server network architecture, the client computer is the one that initiates a request to the server computer, which responds by providing the requested services or resources. The client computer can be any device on the network, such as a laptop, desktop, smartphone, or tablet, while the server computer is usually a powerful computer or a group of computers that manage the network resources and services. The client sends requests to the server for services such as file sharing, printing, or database access, and the server responds by providing these services to the client.

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The correct option is "I, III and IV only". Computers have several advantages, but they do not "think for the user" as stated in option II. Instead, computers are designed to process and execute commands and instructions that are provided to them by users or programs. The advantages of computers include that they operate at high speeds (I), which means that they can process large amounts of data and perform complex calculations in a short period of time. They are also accurate (III), which means that they can perform tasks with a high degree of precision and consistency. Additionally, computers are credible (IV), meaning that they can provide reliable and verifiable information, which is particularly useful in fields such as scientific research and data analysis.

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Page orientation in Microsoft Word refers to the direction in which content is printed on the page. There are two main page orientations available: portrait and landscape. Portrait orientation is the default setting, in which the page is taller than it is wide. This is the most common orientation for documents such as letters, essays, and reports. Landscape orientation, on the other hand, is where the page is wider than it is tall. This orientation is useful for documents such as spreadsheets, tables, and presentations. Therefore, the correct answer to the question is "portrait and landscape".

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The symbol that is not a relational operator in BASIC programming language is "^". Relational operators are symbols used in programming to compare values and determine whether one value is greater than, less than, equal to, or not equal to another value. In BASIC programming language, the relational operators are "<" (less than), ">" (greater than), "<=" (less than or equal to), ">=" (greater than or equal to), "=" (equal to), and "<>" (not equal to). The symbol "^" is not a relational operator in BASIC programming language. It is actually an arithmetic operator used to represent exponentiation, which means raising a number to a power. For example, in BASIC, the expression "2^3" would evaluate to 8, because 2 raised to the power of 3 equals 8. So, to summarize, the symbol "^" is not a relational operator in BASIC programming language, but rather an arithmetic operator used for exponentiation.

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The component directly located inside the computer processor is the Arithmetic Logic Unit (ALU). The ALU is responsible for performing arithmetic and logical operations on data that is passed to it from the computer's memory. This component is essential for carrying out the basic operations of a computer, such as addition, subtraction, and comparison of values. The BIOS, RAM, and ROM are not located inside the processor but are instead separate components that interact with the processor to carry out various functions.

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The term that best describes a set of unorganized facts and figures is "data". Data can be defined as raw, unprocessed information that is collected and stored for later use. This information can be in any form, such as numbers, text, images, or audio. Data becomes useful when it is processed and organized into meaningful information. So, in summary, when we refer to a collection of unorganized facts and figures, we are talking about "data".

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The three descriptions in the question have been shuffled. Each early electronic computer is matched to the description that historically belongs to it.

Reasoning:

• ENIAC (Electronic Numerical Integrator and Computer, 1945) was the first large-scale, electronic, general-purpose machine. It was reprogrammed by rewiring to carry out long, complex sequences of operations.
• EDVAC (Electronic Discrete Variable Automatic Computer, 1949) was the first widely known machine designed to work in binary, and it performed automatic addition, subtraction, multiplication and programmed division.
• UNIVAC (Universal Automatic Computer, 1951) was an electronic digital stored-program computer built for the U.S. Bureau of the Census, and later famous for predicting a presidential election result.

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(a) Convert \(1011011_2\) to hexadecimal

Method 1 (through denary):

\[1011011_2 = (1\times2^6)+(0\times2^5)+(1\times2^4)+(1\times2^3)+(0\times2^2)+(1\times2^1)+(1\times2^0)\]

\[= 64+0+16+8+0+2+1 = 91_{10}\]

Dividing 91 repeatedly by 16: \(91 = 5\times16 + 11\), where \(11 = \text{B}\). Reading the digits gives \(5\text{B}\).

Method 2 (direct grouping): group the bits in fours from the right, \(0101\;1011\). Then \(0101 = 5\) and \(1011 = \text{B}\).

Therefore \(1011011_2 = 5\text{B}_{16}\).

(b) One difference between a hacker and a scammer

A hacker is a person who uses backend technical knowledge of software to gain unauthorised access to the computer systems or accounts of unsuspecting users, with the aim of stealing, altering or exploiting data. A scammer deceives victims through confidence tricks, sending unwanted or inappropriate electronic messages to many recipients, or luring the victim into granting remote access, in order to defraud them. In short, the hacker breaks in through technical means, while the scammer relies on deception to make the victim hand over money or information.

(c) Parts labelled A, B, C and D on the keyboard

• A - Function keys (F1 to F12), the row along the top.
• B - Alphanumeric (typing) keys, the central QWERTY block of letters, numbers and symbols.
• C - Numeric keypad, the calculator-style block of number keys on the right.
• D - Cursor (arrow) control keys, used to move the pointer up, down, left and right.

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(a) One difference between star and bus topologies

In a star topology every computer is connected by its own cable to a central device (a hub or switch), so all data passes through that central point; if one cable fails only that one computer is affected. In a bus topology all computers are connected to a single common cable (the backbone), and if that main cable breaks the whole network goes down.

(b) Four common network devices

1. Hub.
2. Switch.
3. Router.
4. Modem. (Network interface card, bridge and repeater are also acceptable.)

(c) The acronyms in full

• HTML - HyperText Markup Language
• HTTP - HyperText Transfer Protocol
• ISP - Internet Service Provider
• SMTP - Simple Mail Transfer Protocol

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(a) Convert \(1011011_2\) to hexadecimal

Method 1 (through denary):

\[1011011_2 = (1\times2^6)+(0\times2^5)+(1\times2^4)+(1\times2^3)+(0\times2^2)+(1\times2^1)+(1\times2^0)\]

\[= 64+0+16+8+0+2+1 = 91_{10}\]

Dividing 91 repeatedly by 16: \(91 = 5\times16 + 11\), where \(11 = \text{B}\). Reading the digits gives \(5\text{B}\).

Method 2 (direct grouping): group the bits in fours from the right, \(0101\;1011\). Then \(0101 = 5\) and \(1011 = \text{B}\).

Therefore \(1011011_2 = 5\text{B}_{16}\).

(b) One difference between a hacker and a scammer

A hacker is a person who uses backend technical knowledge of software to gain unauthorised access to the computer systems or accounts of unsuspecting users, with the aim of stealing, altering or exploiting data. A scammer deceives victims through confidence tricks, sending unwanted or inappropriate electronic messages to many recipients, or luring the victim into granting remote access, in order to defraud them. In short, the hacker breaks in through technical means, while the scammer relies on deception to make the victim hand over money or information.

(c) Parts labelled A, B, C and D on the keyboard

• A - Function keys (F1 to F12), the row along the top.
• B - Alphanumeric (typing) keys, the central QWERTY block of letters, numbers and symbols.
• C - Numeric keypad, the calculator-style block of number keys on the right.
• D - Cursor (arrow) control keys, used to move the pointer up, down, left and right.

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(a) Two differences between RAM and ROM

(b) Four characteristics of the Windows operating system environment

1. It has a Graphical User Interface (GUI) with icons, menus and windows.
2. It is multi-tasking - it can run several programs at the same time.
3. It is mainly mouse (pointer) driven, with point-and-click and drag-and-drop operations.
4. It uses a desktop with a taskbar and Start menu, and supports plug-and-play devices. (WYSIWYG display is also acceptable.)

(c) Two examples of utility programs

1. Antivirus program.
2. Disk defragmenter (or a file-compression / backup program).

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(a) What are input devices?

Input devices are hardware devices (peripherals) connected to a computer that are used to enter data, instructions, commands or signals into the computer system for processing. They allow the user to interact with and control the computer.

(b) Two input devices

1. Keyboard
2. Mouse

(Scanner, joystick, microphone, light pen, webcam, barcode reader and fingerprint scanner are also acceptable.)

(c) Two uses of logic gates

1. They serve as the building blocks of digital electronic circuits, used to construct the Arithmetic and Logic Unit (ALU), adders and memory cells inside the processor.
2. They are used as decision-making elements in control circuits such as burglar alarms, traffic-light controllers and automatic push-button lock circuits.

(d) Logic gate symbols

(i) OR gate – the output is 1 when at least one of the inputs A or B is 1.

(ii) AND gate – the output is 1 only when both inputs A and B are 1.