Computer Awareness Mixed Quiz: Set 15

The correct answer is B, RJ-45. The registered jack numbered 45 is the eight-pin plastic plug crimped on the end of an unshielded twisted pair Ethernet cable, and it is what clicks into the network port of a computer, a switch or a router. Option A is wrong because a BNC connector, with its bayonet twist lock, belongs to coaxial cable and was used in old bus networks and in test instruments. Option C is wrong because RJ-11 is the smaller six-position jack of an ordinary telephone line, which carries at most two pairs and cannot serve an Ethernet link. Option D is wrong because SC, the subscriber connector, is one of the push-pull connectors used on optical fibre, along with the LC and ST types, and it terminates glass strands carrying light rather than copper pairs carrying electricity.

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 C, 25. To convert a binary number to decimal, write the place values from the right as 1, 2, 4, 8, 16 and so on, multiply each bit by its place value and add the results. The number 11001 has five bits, so the place values from left to right are 16, 8, 4, 2 and 1, and the bits are 1, 1, 0, 0 and 1. The sum is 16 + 8 + 0 + 0 + 1, which equals 25. Option A is wrong because 21 in binary is 10101. Option B is wrong because 23 in binary is 10111. Option D is wrong because 27 in binary is 11011. A useful check is that a binary number ending in 1 is always odd and one ending in 0 is always even, which immediately rules out any even option here.

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, Telephone conversation. Full duplex means both ends can send and receive at the very same moment, and on a telephone call each speaker can talk while still hearing the other, so traffic flows in both directions together. Option A is wrong because a keyboard only sends characters to the computer and never receives any from it, which makes it simplex, a one-way mode. Option B is wrong because a walkie-talkie is the standard example of half duplex: the user must press the button to speak and release it to listen, so the two directions take turns on one channel. Option D is wrong because a television broadcast travels only from the transmitter to the viewer's set, with no return path from the viewer, and is therefore simplex as well.

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, 7. ASCII stands for American Standard Code for Information Interchange. In its standard form it is a seven-bit code, so it can represent 2 raised to the power 7, that is 128 different characters: the English capital and small letters, the ten digit symbols, punctuation marks and a set of control codes. In this code the capital letter A is 65, the small letter a is 97 and the digit character 0 is 48. Option A is wrong because six bits would allow only 64 characters, too few for both cases of the alphabet. Option C is wrong because eight bits describe Extended ASCII and EBCDIC, which reach 256 characters. Option D is wrong because sixteen bits describe the older fixed-width form of Unicode, the standard created so that Devanagari and every other script could be represented.

The correct answer is A, REL. An external stylesheet is attached to a page with a link tag written inside the head section, and the tag needs two things: href, which gives the address of the CSS file, and rel, which tells the browser what the linked file is for. Writing rel equals stylesheet is what marks the file as a set of style rules; leave rel out and the browser has no reason to treat the file as CSS, so the page appears unstyled. B is wrong because style is a separate way of writing CSS, either as a style block in the head or as an attribute on one element, and it has no part in linking an external file. C is wrong because body holds the visible content of the page while the link tag belongs in the head. D is wrong because html is the root element that wraps the whole document and has nothing to do with loading a stylesheet. Exam tip: link rel equals stylesheet with href, placed in the head.

The correct answer is B, TCP. The Transmission Control Protocol first sets up a connection through a three-way handshake, then numbers every segment, waits for an acknowledgement for each and sends it again if none arrives, and finally hands the data to the application in the original order. Because of this care it is used for web pages, email and file transfer, where a missing byte cannot be tolerated. Option A is wrong because UDP is connectionless: it fires datagrams without a handshake, acknowledgement or reordering, which makes it fast and suitable for live voice, video and DNS queries. Option C is wrong because IP is a network layer protocol that only addresses and routes packets and gives no delivery guarantee at all. Option D is wrong because ICMP carries control and error messages, such as the replies used by the ping command, and does not carry user data.

The correct answer is A, B2C (Business to Consumer). In the business to consumer model a firm sells goods or services directly to the person who will use them, and Amazon's retail store is the best known example: a shopper opens the site or the app, puts an item in the cart and buys it, with no wholesaler or trader in between. Every e-commerce model is named in the same way, by who stands at each end of the deal, so learning the four pairs is enough to answer most questions on this topic. B is wrong because business to business means one firm selling to another, the way a parts maker supplies a car factory or IndiaMART links wholesalers. C is wrong because consumer to business is the reverse, where an individual offers a service to a company, as a freelance designer does on a bidding site. D is wrong because consumer to consumer is one individual selling to another, as on OLX or Quikr. Exam tip: B2C is Amazon retail, B2B is IndiaMART, C2C is OLX and C2B is freelancing sites.

The correct answer is B, 0110. The 2's complement is found in two steps. First take the 1's complement by changing every 0 to 1 and every 1 to 0; for 1010 this gives 0101. Then add 1 to that result: 0101 plus 1 equals 0110. So the 2's complement of 1010 is 0110. Computers store negative numbers in 2's complement form because the same adder circuit can then perform both addition and subtraction, which saves hardware. Option A is wrong because 0101 is only the 1's complement, the first step, and forgetting to add one is the commonest mistake in this question. Option C is wrong because 1011 is simply 1010 with the last bit changed. Option D is wrong because 1001 is neither complement of the given number. Remember: 2's complement equals 1's complement plus one.

The correct answer is A, Program counter. In the 8085A microprocessor the program counter is a 16-bit register that always holds the memory address of the next instruction, or op-code, to be fetched. After each fetch it is incremented automatically, and a jump or call instruction loads a new address into it so that control moves elsewhere in the program. Two other registers of the 8085 are often confused with it. The accumulator is the 8-bit register A in which arithmetic and logic results are stored. The stack pointer is a 16-bit register holding the address of the top of the stack, used while saving return addresses and register contents. B and C are wrong for those reasons. D is wrong because instruction pointer is the name Intel's later x86 processors use for the same idea; the 8085 register is called the program counter. Exam tip: 8085 has an 8-bit accumulator and 16-bit program counter and stack pointer.

The correct answer is B, the internet. The internet joins networks in every country through undersea cables, optical fibre on land and satellite links, all of them following the common TCP/IP rules, and no single organisation owns it, so it is rightly called the largest wide area network and a network of networks. Option A is wrong because Ethernet is the family of standards, numbered IEEE 802.3, used to wire a local area network inside a building, not a wide area network. Option C is wrong because Bluetooth is a short range radio technology standardised as IEEE 802.15, which reaches about ten metres and builds a personal area network. Option D is wrong because the intranet of a company is a private network restricted to its own staff; it may be spread over several offices, yet it is far smaller than the public internet and usually rides on it.

The correct answer is D, Transmission speed. The 56 K rating of a modem means it can transfer data at up to 56 kilobits per second, so the figure describes speed, not size. A modem, short for modulator-demodulator, converts the computer's digital signals into analogue form for a telephone line and converts incoming analogue signals back into digital form. Data transfer speed is measured in bits per second and its multiples, kbps, Mbps and Gbps, and the 56 kbps dial-up modem was the fastest standard for ordinary telephone lines before broadband. A is wrong because the physical size of a modem is not rated in kilobits. B is wrong because memory size is measured in bytes such as MB or GB, not in K of this kind. C is wrong because capacity here is loosely worded; the rating fixes the rate of transfer per second. Exam tip: modem speed is in bits per second; storage is in bytes.

The correct answer is C, 13. Hexadecimal has base 16 and therefore needs sixteen different symbols. The digits 0 to 9 serve for the first ten values, and because no single digit exists for the values 10 to 15, the letters A to F are borrowed. The mapping runs A for 10, B for 11, C for 12, D for 13, E for 14 and F for 15. The letter D is the fourth of these letters, so it stands for 13, whose binary form is 1101. Option A is wrong because 11 is B. Option B is wrong because 12 is C. Option D is wrong because 14 is E. A simple memory aid is that the letters continue the count from ten, so the position of the letter in the alphabet after A, plus ten, gives its value.

The correct answer is D, the operating system will return an error indicating that the directory is not empty. The plain remove-directory command is built to delete an empty folder only. In Windows it is rmdir, also written rd, and in Linux it is rmdir; both stop with a message such as "The directory is not empty" when anything is still inside. To remove a folder along with everything in it you have to ask for it: rmdir /s in Windows or rm -r in Linux, which walks through the tree, deletes the contents and then the folder. This guard exists so that a single short command cannot wipe out a large tree by mistake. Option A is wrong because nothing inside is touched without the recursive switch. Option B is wrong because a file system cannot leave files with no parent folder; the entries go together or not at all. Option C is wrong because the plain command does not ask item by item, which is what an interactive option like rm -i does. Exam tip: rmdir empties only, rm -r for the whole tree.

The correct answer is A, Physical Layer. The OSI model has seven layers and they are numbered from the bottom upwards, so Layer 1 is the physical layer, the one that actually carries bits over a copper cable, an optical fibre or a radio link. It fixes voltages, connectors, pin layouts, cable types and data rates, and it has nothing to do with the meaning of the data it carries. The full order from Layer 1 to Layer 7 is physical, data link, network, transport, session, presentation and application. B is wrong because the data link layer is Layer 2, which groups bits into frames and handles MAC addresses and error detection on one link. C is wrong because the transport layer is Layer 4, where TCP and UDP move data from end to end. D is wrong because the network layer is Layer 3, the layer of IP addresses and routing. Exam tip: the sentence Please Do Not Throw Sausage Pizza Away gives physical, data link, network, transport, session, presentation, application in order.

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 C, 255. One byte holds eight bits, and each bit can be either 0 or 1, so the number of different patterns is 2 raised to the power 8, that is 256. Those 256 patterns represent the numbers from 0 to 255 when the byte is unsigned, because counting starts at zero. The largest pattern, 11111111, adds up to 128 + 64 + 32 + 16 + 8 + 4 + 2 + 1, which equals 255. Option A is wrong because 127 is the largest positive value of a signed byte, where the leftmost bit is kept as the sign bit and only seven bits remain for the value. Option B is wrong because 128 is the place value of the leftmost bit alone. Option D is wrong because 256 is the count of patterns, not the largest value, a distinction examiners test often.

The correct answer is C, Double ellipse. In an entity relationship diagram each symbol has a fixed meaning, and an attribute that can hold more than one value for the same entity, such as a person's several phone numbers, is drawn as a double ellipse. The standard set of symbols is worth memorising: a rectangle stands for an entity, a plain ellipse for an ordinary attribute, a diamond for a relationship, a double rectangle for a weak entity, a dashed ellipse for a derived attribute such as age worked out from date of birth, and an underlined attribute for the primary key. A is wrong because a rectangle marks an entity set. B is wrong because a dashed ellipse marks a derived attribute. D is wrong because a diamond marks a relationship between entities. Exam tip: rectangle entity, ellipse attribute, double ellipse multivalued, dashed ellipse derived, diamond relationship, underline key.