Computer Awareness Mixed Quiz: Set 14

The correct answer is A, General Packet Radio Service. GPRS was added to the 2G cellular system so that the same radio channel could carry data in packets instead of holding a circuit open the way a voice call does. Because the user is charged for the volume of data rather than for the minutes of connection, it was called an always-on service, and it made mobile browsing, WAP pages and picture messaging possible; the faster EDGE and then 3G grew out of it. Option B is wrong because the R stands for radio, the medium used, not for route. Option C is wrong because the unit of data in this system is a packet, and package is not a networking term here. Option D is wrong because radiation has nothing to do with the expansion; it only resembles the word radio and is placed there as a distractor.

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 A, (321)8. To turn a binary number into octal, group the bits in threes starting from the rightmost bit, adding leading zeros to complete the last group, because three bits cover the eight octal digits. The number 11010001 splits into 11, 010 and 001, and the first group is written as 011. The group 011 has the value 3, the group 010 has the value 2 and the group 001 has the value 1, so the octal number is 321. Checking in decimal confirms it: 11010001 is 128 + 64 + 16 + 1, which equals 209, and octal 321 is 3 times 64 plus 2 times 8 plus 1, again 209. Option B is wrong because 123 is the same digits reversed. Option C is wrong because 641 would need the bits 110100001. Option D is wrong because 146 in octal equals 102 in decimal.

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 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, 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 C, Star topology. In a star network every computer has its own cable running to a central hub or switch, so the shape resembles the spokes of a wheel. Adding or removing one machine disturbs nobody else and a broken cable affects only that one node, which is why almost every office and laboratory LAN is wired this way; the weakness is that failure of the central device stops the whole network. Option A is wrong because a bus topology has all nodes tapping one common backbone cable with terminators at its two ends. Option B is wrong because in a ring the machines form a closed loop, each joined to two neighbours, and data circulates in one direction using a token. Option D is wrong because a mesh links every node directly to every other node, needing n(n-1)/2 cables for n nodes and having no central device at all.

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 C, 10111. The safest way to handle a binary subtraction in an examination is to convert both numbers to decimal, subtract, and convert the answer back. The first number 10010000 has ones in the places worth 128 and 16, so it equals 144. The second number 1111001 has ones in the places worth 64, 32, 16, 8 and 1, so it equals 121. The difference is 144 minus 121, which is 23. Now convert 23 to binary by repeated division by 2, which gives the remainders 1, 1, 1, 0 and 1 read upwards, that is 10111. Option A is wrong because 11101 equals 29. Option B is wrong because 11011 equals 27. Option D is wrong because 10011 equals 19. Only 10111 equals 23, so C is the answer.

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, 15. In a full mesh every node is joined directly to every other node, so the number of links equals the number of pairs that can be formed from the nodes, given by the formula n(n-1)/2. Putting n equal to 6 gives 6 multiplied by 5, that is 30, divided by 2, which equals 15 cables; each machine also needs 5 network ports, so the port count is n(n-1) in total. Option A is wrong because 12 would be twice the number of nodes and has no basis in the formula. Option C is wrong because 18 is three times the number of nodes and again does not follow from counting pairs. Option D is wrong because 30 is the value of n(n-1), which counts each link twice, once from either end, and must be halved since one cable serves both directions.

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, 4. A bit, short for binary digit, is a single 0 or 1 and is the smallest unit of data a computer handles. Four bits together are called a nibble, which is exactly half of a byte, and the playful name comes from a nibble being a small bite. The nibble matters in practice because one hexadecimal digit is stored in exactly four bits, which is why hexadecimal is such a convenient shorthand for binary. Option A is wrong because two bits form no named unit and can represent only four combinations. Option C is wrong because eight bits make one byte, the unit in which a single character is normally stored. Option D is wrong because sixteen bits make two bytes, often called a word on older machines. Remember the ladder: bit, nibble of 4 bits, byte of 8 bits.

The correct answer is B, Half-duplex. Data can travel between two devices in three modes. In half-duplex mode both devices can send and receive, but only one of them may transmit at any given moment, so the traffic takes turns; a walkie-talkie is the standard example, and older hubs and CB radio worked the same way. In simplex mode data moves in one direction only, as from a keyboard to the computer or from a radio station to a receiver. In full-duplex mode both sides can send and receive at the same time, as in a telephone call or on a modern switched network. A is wrong because simplex allows no return traffic at all. C is wrong because three-quarters duplex is not a recognised mode. D is wrong because only one of the listed modes fits the description. Exam tip: simplex is one way, half-duplex is both ways by turns, full-duplex is both ways together.

The correct answer is C, Network layer. A router joins two or more different networks and decides, for every packet, which outgoing line will carry it towards its destination. It makes that decision by reading the destination IP address, and the IP address is a network layer address, which is the third layer of the OSI model counting from the bottom. Option A is wrong because devices of the physical layer, such as a repeater or a hub, only pass on or regenerate electrical signals and cannot read any address. Option B is wrong because data link layer devices, namely the switch and the bridge, forward frames using MAC addresses and work within one network rather than between networks. Option D is wrong because the transport layer is where TCP and UDP break data into segments and manage acknowledgements; a gateway may operate up to that level and above, but an ordinary router does not.

The correct answer is C, Joint Photographic Experts Group. The format is named after the committee of experts that drew up the standard, which was published in 1992 for compressing photographs. A JPEG file uses lossy compression: it throws away the fine detail the human eye is least likely to miss, so a picture that would need several megabytes as raw data is stored in a few hundred kilobytes. That is why photographs on websites and in phone galleries are saved as .jpg or .jpeg, while logos, line drawings and screenshots are better kept as PNG or GIF, which are lossless. A is wrong because it puts Photography and Exports in place of Photographic and Experts. B is wrong because it replaces Photographic with Pixel. D is wrong on both counts, using Pixel as well as Exports. Exam tip: JPEG is the Joint Photographic Experts Group and is lossy; PNG and GIF are lossless; MPEG is the Moving Picture Experts Group.

The correct answer is B, 1024. Storage units in computing grow in powers of two rather than powers of ten, because addresses are binary. One kilobyte is 2 raised to the power 10 bytes, which equals 1024 bytes. The same step of 1024 continues upward: 1024 kilobytes make one megabyte, 1024 megabytes make one gigabyte and 1024 gigabytes make one terabyte. Option A is wrong because 1000 bytes is the decimal kilobyte used by disc manufacturers in advertising, and it is exactly the trap this question sets. Option C is wrong because 2048 bytes is two kilobytes. Option D is wrong because 512 bytes is half a kilobyte, a figure students recall from the classic disc sector size. In competitive examinations always take one kilobyte as 1024 bytes unless the question itself says otherwise.

The correct answer is C, 48 bits. The Media Access Control address is the permanent physical address written into the network interface card by its maker, and it is 48 bits long, shown to users as twelve hexadecimal digits in six pairs such as 00:1A:2B:3C:4D:5E. The first half identifies the manufacturer and the second half the particular card, so no two cards in the world should carry the same value. Option A is wrong because 16 bits is the width of a port number, which identifies an application and not a machine. Option B is wrong because 32 bits is the length of an IPv4 address, a logical address that changes when the machine moves to another network. Option D is wrong because 128 bits is the length of an IPv6 address, adopted because the supply of 32-bit IPv4 addresses was running out.

The correct answer is B, 128. The octal system has base 8, so it uses only the eight digits from 0 to 7. The general rule is that the largest digit of any number system is one less than its base, which means the digits 8 and 9 can never appear in an octal number. The number 128 contains the digit 8, so it cannot be an octal number, although it is a perfectly valid decimal or hexadecimal number. Option A is wrong as a choice because 377 uses only 3 and 7, both of which are allowed. Option C is wrong because 745 uses 7, 4 and 5, all below 8. Option D is wrong because 66 uses only the digit 6. Apply the same test to binary, where only 0 and 1 are allowed, and to hexadecimal, where 0 to 9 and A to F are allowed.

The correct answer is B, Ring topology. In a ring the machines form a closed loop and a small control frame called a token keeps circulating around it; only the computer holding the token may put data on the ring, and when it finishes it releases the token to the next machine. Because permission is passed around in turn, no two nodes transmit together and collisions cannot occur, which was the chief attraction of the old Token Ring networks. Option A is wrong because a star network depends on a central hub or switch and uses contention or switching, not a circulating token. Option C is wrong because a bus network uses CSMA/CD, in which a node listens to the backbone, sends when it is free and backs off if a collision is detected. Option D is wrong because a tree is only a hierarchy of star segments and inherits their access method.