12th Standard Computer Applications: Previous Year Mixed Test

Explanation. JPEG stores an image as a grid of pixels, so it is a raster format; CDR, SVG and EPS are vector formats.

Explanation. In PageMaker, File → Place is used to import text or graphics into the document.

Explanation. ALTER is the DDL command that changes the structure of an existing database or table, e.g. adding or modifying columns.

Explanation. PHP script files are saved with the .php extension.

Explanation. A function is a named block of code that performs a specific task and can be called whenever needed.

Explanation. The break statement ends a case and exits the switch block; without it execution falls through to the next case.

Explanation. In for (init; condition; increment), the increment part runs after each iteration and updates the loop variable.

Explanation. Check boxes let the user tick any number of options, whereas radio buttons allow only one choice from a group.

Explanation. The MySQLi (MySQL Improved) extension was introduced with PHP 5.0, and PHP 5 and later versions support it.

Explanation. Gmail is an e-mail service; Twitter, LinkedIn and Facebook are social media platforms.

Explanation. Wi-Fi stands for Wireless Fidelity, a wireless LAN technology.

Explanation. The RJ-21 connector, used for multi-line telephone and network connections, is known as the champ (Amphenol) connector.

Explanation. Government-to-Government systems are of two types: internal facing (within one government) and external facing (between governments).

Explanation. UPI is the Unified Payments Interface developed by NPCI for instant bank-to-bank mobile payments.

Explanation. EDI architecture has four layers: semantic (application), standards translation, packing (transport) and physical network.

Explanation. Multimedia combines five major components: text, images, sound, video and animation.

Explanation. In PageMaker, the Zoom tool magnifies (or reduces) a selected portion of the page; the Hand tool only scrolls the page.

Explanation. Ctrl+A (Select All) selects the entire text of the document; Ctrl+C copies the selection.

Explanation. The === operator is the identical operator: it returns true only when both operands are equal and of the same data type. == is "equal" and = is assignment.

Explanation. PHP has three types of arrays: indexed arrays, associative arrays and multidimensional arrays.

Explanation. if...else executes one block when the condition is true and another when it is false, so it is a conditional statement.

Explanation. A do...while loop runs its body once before testing the condition, so it prints 4; then $i becomes 5 and 5 <= 3 is false, so the loop stops. The output is just 4, which is not among options (a)-(c).

Explanation. The foreach loop is designed to go through each element of an array one by one without using an index counter.

Explanation. A while loop tests its condition before entering the loop body, so it is an entry-check loop; do...while is the exit-check loop.

Explanation. A computer network is a set of computers connected together to share resources and information.

Explanation. FTP stands for File Transfer Protocol, the standard protocol for transferring files between computers over a network.

Explanation. Tim Berners-Lee invented the World Wide Web in 1989 at CERN.

Explanation. Digital publishing websites act as online publishers and host e-books on their own websites.

Explanation. An extranet extends an organisation's private network to authorised outsiders such as suppliers, vendors, partners and customers; an intranet is for employees only.

Explanation. The Transportation Data Coordinating Committee (TDCC) published the first industry-specific EDI standard in 1975, for the transport industry.

Explanation. AIFF (Audio Interchange File Format) is an audio file format developed by Apple Inc.

Explanation. SELECT is the DQL command that retrieves data from tables; Insert, Update and Delete are DML commands that change data.

Explanation. echo displays strings or other data on the screen; for and while are loops and switch is a conditional statement.

Explanation. The break statement ends the matching case and exits the switch block.

Explanation. $i starts at 5 and decreases by 1 while $i >= 1, so 5, 4, 3, 2, 1 are printed (each on a new line), i.e. 54321.

Explanation. In PHP the MySQLi function mysqli_close() takes the connection object returned by mysqli_connect() and closes that connection.

Explanation. A mobile (cellular) network divides the land area into cells, each served by at least one fixed transceiver (base station).

Explanation. An IPv6 address is 128 bits long, while an IPv4 address is 32 bits.

Explanation. RJ21 is a 50-pin telephone connector commonly called the champ connector (Amphenol connector).

Explanation. In PageMaker, File > Place is used to import text or graphics into the publication.

Explanation. SME stands for Small and Medium-sized Enterprises, businesses that use computer networks for communication and trade.

Explanation. A debit card deducts money from the bank account immediately (pay now); a credit card is pay later and a stored value card is pay before.

Explanation. The root name servers are maintained and coordinated by IANA (Internet Assigned Numbers Authority).

Explanation. Authenticity, privacy and confidentiality are e-commerce security elements; phishing is a threat (a fraud to steal details), not a security element.

Explanation. A user-defined function in PHP is declared with the keyword function, e.g. function add() { ... }.

Explanation. Web casting is the live broadcasting (telecasting) of real-time programs such as events and shows over the Internet.

Explanation. In PageMaker, the area inside the dark border is the page, and the area outside it is the pasteboard, used to keep objects temporarily; objects on it are not printed.

Explanation. MySQL is a Relational Database Management System (RDBMS): data is stored in tables of rows and columns and accessed using SQL.

Explanation. According to the server-side scripting usage statistics quoted in the textbook, about 78.9% of websites are developed using PHP.

Explanation. An associative array stores data as key-value pairs, where each value is accessed using a named key instead of a numeric index.

Explanation. Loops that run a block of code a specified (fixed) number of times are called bounded loops; loops that repeat until a condition changes are unbounded loops. A for loop is one example of a bounded loop, but the category itself is called bounded loops.

Explanation. In a group of radio buttons only one option can be selected at a time, whereas check boxes allow several selections.

Explanation. In the history of networking, SAGE and SABRE were early systems and ARCNET was an early LAN; the new fibre optics period brought speeds towards gigabit levels.

Explanation. RFID (Radio Frequency Identification) uses radio signals to identify and track objects through tags attached to them.

Explanation. In DNS, each node label can have at most 63 characters, while a full domain name can have at most 255 characters.

Explanation. Fiber optic cables, used for long-distance high-speed links, are laid deep underground so that they are protected from damage.

Explanation. The dotcom phenomenon refers to the rapid growth of Internet-based companies (whose names ended in .com) in the late 1990s.

Explanation. NS2 (Network Simulator version 2) is an open source network simulator; C++ and TCL are the languages used to build and script it.

Explanation. PGP stands for Pretty Good Privacy, an encryption program used to secure e-mail and data.

Explanation. The Zoom tool in PageMaker magnifies (or reduces) a particular area of the page; the Hand tool only scrolls the page.

Explanation. JPEG stands for Joint Photographic Experts Group, the committee that created this common compressed image format.

Explanation. Character formatting changes the look of individual characters, such as bold, italic, underline, font and size, so all three listed properties belong to it.

Explanation. An Entity-Relationship (ER) diagram graphically shows the entities, their attributes and the relationships among them, giving the logical structure of the database.

Explanation. PHP script files are saved with the default extension .php so that the web server passes them to the PHP interpreter.

Explanation. By definition, an array is the concept that stores more than one value of the same data type (homogeneous) in a single array variable; indexed and multi-dimensional arrays are only its types.

Explanation. The foreach loop works only on arrays: it takes each element of the array in turn without needing a counter.

Explanation. SQL stands for Structured Query Language, the standard language used to create, query and manage relational databases.

Explanation. An extranet extends a company’s private network over the Internet so that outside suppliers, partners and customers can securely share its business information; an intranet is for employees only.

Explanation. Tim Berners-Lee invented the World Wide Web in 1989 at CERN; Pascal, Napier and Babbage were pioneers of calculating machines.

Explanation. Both statements are true: the first wave of dotcom companies were mostly American, which is why their web-sites were only in English, so (R) explains (A).

Explanation. The parties in a credit card transaction are the card holder, merchant, acquirer (merchant’s bank), issuer and card network; a marketing manager is not one of them.

Explanation. Websites protected by SSL use the HTTPS protocol, so their address begins with https:// (usually with a padlock icon in the browser).

Explanation. EDIFACT standards are released as versions called directories (for example D.01B), each containing the message types valid for that release.

Explanation. PHP code runs on the web server, and only the resulting HTML is sent to the browser, so PHP is a server side scripting language.

Explanation. The if...else statement tests a condition and executes exactly one of two blocks: the if block when true, the else block when false.

Explanation. JPEG stands for Joint Photographic Experts Group, the committee that created this compressed image format.

Explanation. RTF is a text format, TGA an image format, OGG an audio format and MPEG a video format, so the matching is (1)-(iv), (2)-(i), (3)-(ii), (4)-(iii).

Explanation. In PageMaker the Zoom tool magnifies (or reduces) a selected area of the page; the Hand tool only scrolls the view.

Explanation. A weak entity set lacks attributes to form its own primary key and depends on a strong (owner) entity set for identification.

Explanation. The default PHP syntax opens with <?php and closes with ?>; <? ... ?> is only the short-open-tag form.

Explanation. The if...else statement runs one block when the condition is true and the other block when it is false, so exactly one of the two options is performed.

Explanation. PHP supports for, while, do...while and foreach loops, so all the listed loops are supported.

Explanation. mysqli_close($connection) takes only one parameter: the connection link to be closed.

Explanation. A group of computers connected together to share data and resources is a network; a node is a single device in it.

Explanation. Wi-Fi means Wireless Fidelity, a wireless LAN technology based on IEEE 802.11.

Explanation. The Domain Name Space is the hierarchical tree structure that holds (maintains) the directory of all domain names; DNS is the service that uses it to resolve names to IP addresses.

Explanation. Open source software makes its source code freely available for anyone to view, modify and share; freeware is free to use but usually without source code.

Explanation. Tangible goods are physical items that can be touched; mobile apps are digital (intangible) goods.

Explanation. Credit cards are 'pay later', debit cards are 'pay now' (money is taken from the account immediately) and stored value cards are 'pay before'. Only Debit Cards - Pay now is correct.

Explanation. The first industry-specific EDI standard was published in 1975 by the Transportation Data Coordinating Committee (TDCC) for the transport industry.

Explanation. MIDI stands for Musical Instrument Digital Interface. None of the printed options is exactly correct (misprint); option (d) is the closest intended answer, differing only in the last word.

Explanation. Ctrl + N opens a new PageMaker document (the Tamil version asks for opening a new document). An existing file is opened with Ctrl + O, which is not among the options, so Ctrl + N is the intended answer.

Explanation. A row (horizontal entity) of a table is called a record or tuple; the vertical entity is a column or field.

Explanation. CREATE, ALTER and DROP define or change the structure of the database (DDL). INSERT adds data into a table, so it is a DML command.

Explanation. In PHP, // starts a single-line comment, while /* */ encloses multi-line comments. The shell-style # also works for a single line, so the paper has two valid options; // is the standard answer.

Explanation. The textbook classifies PHP functions into three types: user-defined functions, pre-defined (built-in) functions and parameterized functions.

Explanation. $x is declared without a value, so it is NULL. In the loose comparison NULL == 0 is true, so the if block runs and prints hi.

Explanation. The for loop is considered the most complex loop in PHP because its header combines initialization, condition and increment in one statement.

Explanation. A query is a request to retrieve data or information from one or more database tables, for example a SELECT statement.

Explanation. Each computer or device connected to a network is called a node.

Explanation. TCP stands for Transmission Control Protocol, which provides reliable, connection-oriented data transfer.

Explanation. The labels of a domain name are separated by dots, for example www.tn.gov.in.

Explanation. Tim Berners-Lee invented the World Wide Web in 1989 at CERN.

Explanation. An IPv4 address is 32 bits long and can be written in binary notation or in dotted-decimal notation (e.g. 192.168.1.1), so both (a) and (b) are correct. Hexadecimal is used for IPv6.

Explanation. Wi-Fi stands for Wireless Fidelity, a wireless LAN technology based on IEEE 802.11.