Computer Awareness Mixed Quiz: Set 26

The correct answer is C, the NOT gate. It is the only gate that takes a single input, and it simply reverses the logic level it receives, giving 1 for an input of 0 and 0 for an input of 1; because the output is the inverse or complement of the input, the circuit is called an inverter. In Boolean notation it is written with a bar or a prime over the variable, and in a diagram it is a triangle with a small circle at its tip. A is wrong because an AND gate has two or more inputs and does not reverse anything. B is wrong for the same reason. D is wrong because a NAND gate inverts only the result of an AND operation and normally has two inputs, although it is worth remembering that a NAND gate with both of its inputs joined together does behave as an inverter, which is one of the proofs that NAND is a universal gate.

The correct answer is B, NAND and NOR. Each of these gates alone is enough to build every other gate and so every logic circuit: a NAND with its two inputs tied together acts as a NOT, two NANDs in sequence give an AND, and a suitable arrangement of three gives an OR, and the same can be done entirely with NOR gates. That is why chip makers sell packages containing only one gate type. A is wrong because AND and OR cannot produce a complement by themselves; without a NOT they can never invert a signal. C is wrong because XOR and XNOR are themselves derived gates, built from the basic three, and neither can generate the full set on its own. D is wrong because NOT with AND can indeed build everything, but the pair is not given the name universal gates; the term is reserved for the two single gates that suffice by themselves.

The correct answer is B, Windows + E. The letter E stands for Explorer, and this combination opens File Explorer, earlier called Windows Explorer, which is the program used to browse drives, folders and files. A is wrong because Windows and D together show the desktop by minimising every open window, and pressing it again restores them. C is wrong because Windows and L together lock the computer and return to the sign-in screen, which is the correct habit when leaving a machine unattended. D is wrong because Windows and R together open the Run dialog box, into which a command such as cmd or control can be typed. Candidates should also remember Alt and Tab for switching windows, Alt and F4 for closing the active window, and Ctrl with Shift and Escape for Task Manager.

The correct answer is B, Datasheet. In a database such as Microsoft Access, the view that shows a table as rows and columns, looking like a spreadsheet grid, is called Datasheet view. Each row of that grid is one record and each column is one field, and the names along the top come from the field names set in Design view. Datasheet view lets you type data straight in, sort it, filter it and widen columns, while Design view is where the data type, field size and primary key are fixed. Queries and forms can also be opened in Datasheet view, so the name belongs to the display format, not to one object. Option A is wrong because a record is a single row of the grid, one complete entry, not the grid itself. Option C is wrong because a query is a saved question that pulls out selected rows; it is a database object. Option D is wrong because 'Tables' names the objects being displayed, while the question asks what the grid-like view is called. Exam tip: Access tables have two main views — Datasheet for data, Design for structure.

The correct answer is B, MS Access. Access stores data in separate tables that are joined to one another through keys, which is what makes it relational, and it provides tables, queries, forms, reports, macros and modules to work with that data. It ships with the professional editions of Office. Option A, MS Excel, is a spreadsheet; it arranges data in a single grid of rows and columns and can sort, filter and calculate, but it has no concept of a relationship between tables and is not a database management system. Option C, MS Publisher, is a desktop publishing program for brochures, cards and newsletters. Option D, MS OneNote, is a digital notebook for loose notes, clippings and sketches. Papers often set Excel against Access on purpose, so remember the dividing line: a spreadsheet keeps one table, a database keeps many tables and the links between them.

The correct answer is C, Graphics. In multimedia, graphics is the broad word for every kind of visual element a computer can store and show, so drawings, photographs, movies and simulations all sit inside it. The usual list of multimedia elements is text, graphics, audio, video and animation, and in that list graphics covers both pictures made by hand on the screen and pictures captured from the real world. Graphics are stored either as bitmaps, made of pixels, as in a JPEG or BMP photograph, or as vectors, made of lines and curves described by equations, as in a drawing or a CAD file. A is wrong because animation is only one kind of visual, a sequence of frames shown fast enough to look like movement. B is wrong because an image is a single still picture, so it is narrower than the four things listed. D is wrong because text is made of characters and carries no picture. Exam tip: multimedia elements are text, graphics, audio, video and animation; bitmap graphics use pixels, vector graphics use equations.

The correct answer is B, Tim Berners-Lee. He was a British scientist working at CERN in Switzerland when he wrote the proposal for the World Wide Web in 1989, and he built the first browser, WorldWideWeb, later renamed Nexus; the first website went live in 1991. He also founded the World Wide Web Consortium in 1994. Option A, Charles Babbage, belongs to the nineteenth century and is called the father of the computer for his Difference Engine and Analytical Engine, not to the Web at all. Option C, Vinton Cerf, with Robert Kahn designed the TCP/IP protocols and is called a father of the internet, which is the network beneath the Web, so he is the classic distractor in this question. Option D, Marc Andreessen, led the team that wrote Mosaic in 1993 and later founded Netscape, but he came after Berners-Lee and invented neither the Web nor the first browser.

The correct answer is C, Netscape. Netscape Navigator, released in 1994 by Netscape Communications, the company founded by Marc Andreessen and Jim Clark, was the first web browser sold as a commercial product. It was the browser that carried the web to ordinary users in the mid nineties and at its peak held most of the market, before losing the browser war to Internet Explorer. A is wrong because Mosaic, built in 1993 at the NCSA of the University of Illinois, was the first widely used graphical browser but was academic software given away free, not a commercial product. B is wrong because Mozilla is the open source project born in 1998 from Netscape's released source code; its browser Firefox came in 2004 and is free. D is wrong because Internet Explorer arrived in 1995 and was bundled free with Windows rather than sold. Exam tip: Mosaic 1993 first popular graphical browser, Netscape Navigator 1994 first commercial browser, Firefox 2004 from the Mozilla project.

The correct answer is C, eight. Each input can take one of two values, so for three inputs the number of distinct combinations is two multiplied by itself three times, that is two raised to the power three, which is eight. The same rule gives four rows for two inputs, sixteen for four inputs and thirty-two for five. A is wrong because three is simply the number of inputs, not of combinations, and no truth table has as many rows as it has input columns. B is wrong because it comes from multiplying the number of inputs by two, the commonest error on this question; the relationship is a power of two, not a product. D is wrong because nine is three squared, which reverses base and exponent; the base must always be two, since each variable is binary. Checking that the table has the right number of rows is also a quick way to catch a missing combination.

The correct answer is A, Write Once, Read Many. WORM describes a storage medium on which data can be written a single time and after that only read, never altered or erased. A CD-R or a DVD-R is the everyday example, because once the disc has been burnt the marks made in its dye layer are permanent. Since the record cannot be changed later, WORM media are used for archives, bank and hospital records, court evidence and audit trails, where proof that nothing was tampered with matters more than the freedom to edit. Modern systems offer the same guarantee in software on hard disks and cloud storage. B is wrong because Word On RAM Memory is not a storage term at all. C is wrong because it mixes optical recognition with malware, and the worm that is malware is an ordinary word, not an acronym. D is wrong because WORM has nothing to do with wireless working. Exam tip: WORM means Write Once Read Many, as on CD-R and DVD-R, and is used for tamper-proof archives.

The correct answer is B, taskbar. The taskbar holds the Start button, the search box, the buttons of pinned and running programs, and at its right the notification area or system tray with the clock, network and volume icons. It can be moved to another edge of the screen or hidden, but it stays at the bottom by default. A is wrong because the title bar is the top strip of a single window, carrying the name of the document and the minimise, maximise and close buttons. C is wrong because the status bar is the strip at the bottom of a program window that shows information such as the page and word count in a word processor. D is wrong because a scroll bar is the vertical or horizontal bar used to move the view within a window whose contents do not fit on the screen.

The correct answer is D, the input tag with its type attribute set to checkbox. HTML has no separate checkbox element at all. Every simple form control is written with the single input tag, and the type attribute decides what the browser draws, whether that is text, password, radio, checkbox, submit, file or hidden. So a checkbox is made by writing input and setting type to checkbox, while the name and value attributes tell the server which boxes were ticked. Several checkboxes may share one name, which lets a user pick more than one answer; radio buttons that share a name allow only one choice. Option A is wrong because checkbox is written there as a bare word instead of as the value of the type attribute. Option B is wrong because no checkbox element exists in HTML. Option C is wrong because the equals sign is placed straight after the tag name rather than inside a proper attribute. Exam tip: one input tag, many controls, and the type attribute is what changes.

The correct answer is B, .accdb. From Access 2007 onwards, the default database format changed and files are saved with the extension .accdb, which stands for Access database and supports features such as multivalued fields and attachment data types. Option A, .mdb, was the extension of the earlier format used up to Access 2003; it can still be opened for compatibility, which is why it is the favourite distractor in this question. Option C, .adb, is not an Access format at all. Option D, .dbf, is the old dBase file format, used by dBase, FoxPro and several statistical packages, and it can be imported into Access but is not written by it. The pattern to notice is that Office 2007 added a letter to the extensions of the whole suite, giving .docx for Word, .xlsx for Excel, .pptx for PowerPoint and .accdb for Access.

The correct answer is C, C2B. In the consumer-to-business model the consumer names the price or the terms and the business then accepts or declines the offer, so the usual direction of an offer is reversed. Reverse-auction travel sites, where a traveller bids a price for a hotel room, and freelancers who quote their own rate to companies are everyday examples. The model spread with the internet, which let one individual reach many firms at once. A is wrong because B2B commerce is trade between two businesses, such as a parts maker supplying a car factory. B is wrong because B2C commerce is a business selling directly to the end consumer, as a shopping website does. D is wrong because C2C commerce links one consumer with another through a platform, as online classified and resale sites do. Exam tip: read the pair in order - the first letter is who makes the offer, the second is who responds, so in C2B the consumer sets the price.

The correct answer is B, Uniform Resource Locator. A URL is the complete address of a resource on the Web, and it has three visible parts: the protocol, such as https, the domain name, such as www.example.in, and the path to the particular page inside that site. Option A, Universal Resource Link, mixes the right idea with the wrong words; the first word is uniform, not universal, and the last is locator, not link, so it is wrong even though it sounds familiar. Option C, Unified Retrieval Locator, invents a term that no standard uses and should be rejected at sight. Option D, Uniform Reference Line, keeps only the first word correctly and is otherwise meaningless. Examiners rely on candidates half-remembering the expansion, so learn the three words in order: uniform, resource, locator.

The correct answer is A, the first generation. Machines such as ENIAC, EDVAC and UNIVAC-I ran on thousands of vacuum tubes, which made them enormous, power-hungry and dependent on constant cooling. They were programmed in machine language and used punched cards for input and magnetic drums for storage.

Option B, the second generation, replaced the tube with the transistor invented at Bell Laboratories in 1947, which cut the size and heat sharply and allowed assembly language and the first high-level languages such as COBOL and FORTRAN. Option C, the third generation, is defined by the integrated circuit demonstrated by Jack Kilby in 1958, and brought the keyboard, the monitor and the operating system. Option D, the fourth generation, begins with the microprocessor and very large scale integration, the Intel 4004 of 1971 being the first commercial one. Learn the chain tube, transistor, integrated circuit, microprocessor in order.

The correct answer is B, 1. This is the complement law for addition, which corresponds to the OR operation. Whatever value A takes, one of A and its complement must be 1, and an OR gate gives 1 whenever any input is 1, so the expression is 1 in both cases. A is wrong because 0 is the answer to the companion law for multiplication, A multiplied by the complement of A, where one factor is always 0 and an AND gate therefore gives 0; the two complement laws are routinely interchanged in papers. C is wrong because A plus A, not A plus its complement, returns A, which is the idempotent law. D is wrong because nothing in Boolean algebra makes a sum collapse to the complement of one of its terms. Keep the pair together in memory: a variable OR its complement is 1, a variable AND its complement is 0.

The correct answer is C, it is deleted directly and does not go to the Recycle Bin. The Recycle Bin is maintained for the fixed drives of the computer; removable media such as pen drives and memory cards, and files deleted over a network drive, have no Recycle Bin, so Windows warns that the file will be deleted permanently. A is wrong because a pen drive keeps no Recycle Bin of its own for this purpose. B is wrong because the Bin of the computer stores only what was deleted from its own hard disk partitions, not from removable media. D is wrong because no hidden folder named Deleted is created; recovery in such a case needs special software, which is why candidates should treat a deletion from a pen drive as final and copy important files before clearing them.

The correct answer is B, primary key. A primary key is a field, or a combination of fields, whose value is different in every record and never left empty, so it can be used to pick out one record with certainty; an AutoNumber field is the usual choice because Access fills it in by itself. Option A, foreign key, is a field in one table that stores the primary key value of another table, and it is the device that creates a relationship between two tables, but it need not be unique. Option C, an index field, is one on which an index is built to make searching and sorting faster; an index may allow duplicates and is not the same as a key. Option D, a lookup field, shows a list of values drawn from another table or a fixed list to make data entry easier. A table may have only one primary key but many indexes and many foreign keys.

The correct answer is C, Blink. The browser engine, also called the layout or rendering engine, is the part that turns the HTML received from a server into the page you see, and Chrome has used Blink since 2013; Opera and Microsoft Edge use the same engine today, which is why pages look alike in all three. Option A, Gecko, is the engine of Mozilla Firefox, and it grew out of the old Netscape code, so it is the right answer to a different question. Option B, Trident, was the engine of Microsoft's Internet Explorer and is no longer in use now that Edge has replaced that browser. Option D, WebKit, is Apple's engine and powers Safari; Blink itself began as a branch of WebKit, which is why the two names are so often confused in papers.