Computer Awareness Mixed Quiz: Set 17

The correct answer is B, worm. A worm carries its own code, finds other machines through the network and copies itself to them without any help from the user, which is why worms can spread across the world in hours. Option A is wrong because a virus must attach itself to a file or program and spreads only when that host is opened, copied or run, so human action is always needed. Option C is wrong because a Trojan horse neither attaches nor replicates; it is disguised as useful software and depends entirely on the user installing it, after which it opens a back door for the attacker. Option D is wrong because adware merely displays unwanted advertisements and gathers browsing habits, and although it is a nuisance it does not spread on its own. The one-line distinction to memorise is that a virus needs a host and a user, a worm needs neither.

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, TRUNCATE. TRUNCATE empties a table in one operation, leaving the columns, data types and constraints in place so that the table can be filled again at once; because it changes the object rather than selected rows it is grouped with the Data Definition Language and it is much faster than deleting row by row. Option A is wrong because DELETE is a Data Manipulation Language command that removes only the rows a WHERE clause selects and can be undone with ROLLBACK before the transaction is committed. Option B is wrong because DROP destroys the table itself, so the structure disappears along with the data. Option D is wrong because ERASE is not an SQL command at all; it is a distractor built from ordinary English. The DELETE against TRUNCATE difference is a favourite one-mark question.

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 A, ransomware. It locks the files by encrypting them and shows a demand for money, usually in a crypto currency, in exchange for the key; the WannaCry outbreak of 2017 struck hospitals, factories and offices in many countries and is the example examiners quote. Option B is wrong because a rootkit hides an intruder's presence by burying itself in the operating system so that scanners and system tools do not report it; it conceals rather than extorts. Option C is wrong because a keylogger silently records every key pressed and sends the log to the attacker, which is a way of stealing passwords. Option D is wrong and is not malware at all: a honeypot is a decoy computer set up on purpose by defenders so that attackers waste effort on it and can be studied. Regular offline backups are the standard protection against ransomware.

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 C, primary key. The designer picks one candidate key as the primary key of a table, and the database then enforces two rules on it: its value must be different in every row, and it can never be left null, since a missing value would make a row impossible to identify. Option A is wrong because a foreign key holds the primary key values of another table to create a link, and it may be null when no related row exists. Option B is wrong because an alternate key is simply a candidate key that was not chosen as the primary key, so it is unique but is not the identifying key of the table. Option D is wrong because a super key is any set of attributes that identifies a row, and it may carry extra attributes that are not needed for uniqueness.

The correct answer is B, Meta Search Engine. A meta search engine keeps no index of its own. It hands the user's query to several other search engines at the same time, collects what they send back, removes repeated hits and shows one merged list. Because it borrows from many sources, a single search covers more of the web than any one engine would on its own. Dogpile and Startpage work in this way. A is wrong because advanced search only means the extra filters an ordinary engine offers, such as date, file type or exact phrase, while it still searches its own index. C is wrong because search tool is a loose term for any utility that finds files or text, not a defined class of engine. D is wrong because Boolean searching refers to using AND, OR and NOT inside one engine, not to querying other engines. Exam tip: meta means about, so a meta search engine searches the searchers.

The correct answer is B, CERT-In, the Indian Computer Emergency Response Team, which works under the Ministry of Electronics and Information Technology and is the national agency for collecting, analysing and issuing alerts on cyber incidents and for coordinating the response to them. Option A is wrong because the National Informatics Centre builds and runs the information technology infrastructure of government departments; it is a service provider, not the incident response agency. Option C is wrong because the Telecom Regulatory Authority of India regulates tariffs and the quality of telecom service and has no incident response role. Option D is wrong because the Standardisation Testing and Quality Certification directorate certifies the quality of information technology products and services. Also remember the National Critical Information Infrastructure Protection Centre for critical sectors and the Cyber Swachhta Kendra for cleaning botnets.

The correct answer is A, HREF. The href attribute of the anchor tag carries the address the browser should open when the link is clicked, so href alone decides where a link leads. The text written between the opening and closing anchor tags is what the reader sees and clicks. The value of href can be a full web address, a path to another file on the same site, or a point inside the same page written after a hash. B is wrong because src supplies the source file for images, scripts and iframes, not for links. C is wrong because link is a separate element placed in the head section to attach stylesheets; it is not an attribute of the anchor tag. D is wrong because HYPERLINK is not an HTML attribute at all, it is the name of a spreadsheet function. Exam tip: remember the pair — href points a link somewhere, src pulls a file in.

The correct answer is B, foreign key. A foreign key is the column that stores values belonging to the primary key of another table, so a marks table can carry the roll number of a student table and the two tables can then be joined; the database uses it to enforce referential integrity, refusing a value that does not exist in the parent table. Option A is wrong because a candidate key is a minimal set of attributes that identifies rows within the same table and points nowhere else. Option C is wrong because a composite key is a primary key built from two or more columns taken together, such as roll number with subject code. Option D is wrong because a secondary index only speeds up searching on a column and creates no relationship between tables at all.

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, humans. CAPTCHA stands for Completely Automated Public Turing test to tell Computers and Humans Apart, and it is the distorted text, image grid or check box that a site shows before accepting a form, so that automated programs cannot register accounts, book tickets in bulk or guess passwords by the thousand. The name recalls Alan Turing, whose test asked whether a machine could pass for a person. Option A is wrong because consoles are gaming or control devices and have no place in the expansion. Option C is wrong because a CAPTCHA does not separate hackers from honest users; a human attacker can solve it, so it stops automation, not intent. Option D is wrong because a host is any computer connected to a network, again unrelated. Examiners ask this expansion word for word, so learn it exactly.

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, isolation. Isolation means that transactions running at the same time do not see one another's incomplete work, so two clerks booking the last seat cannot both succeed; the database behaves as though the transactions ran one after the other. The four properties in full are atomicity, consistency, isolation and durability. Option A is wrong because integrity is a general term for correctness of data, enforced by constraints such as primary and foreign keys, and it is not the I of ACID. Option B is wrong because indexing is a technique for faster searching and has nothing to do with transaction guarantees. Option D is wrong because inheritance is a feature of object oriented programming, where a class takes properties from a parent class. Atomicity means all steps happen or none, and durability means a committed change survives a crash.

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 A. The name counts the days the software maker has had to fix the flaw, and that number is zero: the attacker knows of a weakness that the vendor has not discovered or not yet repaired, so no update protects the user and even a fully patched system is exposed. Such flaws are valuable and are traded quietly, which is why the attacks are often aimed at high value targets. Option B is wrong because an empty password is simply a case of weak authentication, defeated by a basic password policy. Option C is wrong because an attack needs a running system to act on; a machine that is switched off is out of reach over the network. Option D is wrong because bandwidth measures the capacity of a link and has nothing to do with software flaws. Defence rests on quick patching, layered controls and behaviour based detection.

The correct answer is B, degree. The degree of a relation counts its attributes, that is its columns, so a student table holding roll number, name, class and marks has degree four whatever the number of students in it. Option A is wrong because cardinality counts the tuples, that is the rows of the table, so the same student table with two hundred students has cardinality two hundred. Option C is wrong because a domain is the set of permitted values for one attribute, for example the letters A to E for a grade column, and it is not a count at all. Option D is wrong because tuple count is only another name for cardinality, so it repeats the error in option A. Examiners frequently swap degree and cardinality in the options, so read the words attribute and tuple carefully before choosing.

The correct answer is B, asymmetric encryption, also called public key encryption. Anyone may hold the public key and use it to encrypt a message, but only the holder of the matching private key can decrypt it, so no secret has to be exchanged in advance; RSA is the standard example, and the same pair used the other way round produces a digital signature. Option A is wrong because symmetric encryption, such as AES or the older DES, uses one shared secret key for both operations and is fast but requires a safe way to pass that key. Option C is wrong because hashing is a one-way function that turns data into a fixed length digest for checking integrity and cannot be reversed to recover the message. Option D is wrong because compression only reduces the size of a file and provides no secrecy at all.

The correct answer is B, second normal form. A table is in second normal form when it is already in first normal form and no non-key attribute depends on only a part of a composite primary key; such a partial dependency is removed by moving that attribute into a table of its own. Option A is wrong because first normal form only requires that every value be atomic and that repeating groups be removed, which says nothing about composite keys. Option C is wrong because third normal form removes transitive dependency, where one non-key attribute depends on another non-key attribute rather than on a part of the key. Option D is wrong because Boyce-Codd normal form is a stricter version of the third form, requiring every determinant to be a candidate key. Learn the order: 1NF atomic values, 2NF partial, 3NF transitive.