Computer Science: Unit-wise Objective Question Bank

Computer Science in grade 8 is examined by your own school, in a written paper of 50 marks and two hours, beside the practical work in the lab. Group A of that paper is ten one-mark objective items. They are the quickest marks in the paper and the easiest to lose: a full form remembered wrongly, a hub confused with a switch, a binary number read from the wrong end, a QBASIC MOD worked out as a division. This chapter drills those items lesson by lesson for all twenty lessons of the Computer Science 8 book, in the same order as the book.

Each section opens with a facts line — the few facts that the items of that lesson actually use. Then come eight to ten items, and then a key that gives each answer with a one-line reason. Work an item in under a minute, check it in ten seconds, and move on. The reasons matter more than the letters: a reason you can repeat is a mark you will not lose next time.

23.1 Fundamentals of Computer

Facts. A computer accepts data, processes it under a program, stores it and gives information (Latin computare, to calculate). Data are raw facts; information is processed data. Hardware can be touched; software is a set of programs. IPOS: input → CPU (control unit directs, ALU calculates and compares) → output, with storage (RAM temporary; hard disk, SSD, pen drive permanent). Characteristics: speed (ms, μs, ns), accuracy (GIGO), diligence, versatility, storage, automation. 1 KB = 1024 bytes; 1 GB = 1024 MB.

1. Processed, meaningful data is called [1]adatabinformationcan instructionda program
2. Which part of the CPU compares two marks to find the larger? [1]acontrol unitbarithmetic logic unitcRAMdhard disk
3. A teacher typed 29 instead of 92, so a student's percentage came out wrong. This illustrates [1]adiligencebGIGOcversatilitydautomation
4. Which device is both an input and an output device? [1]ascannerbprinterctouch screendspeaker
5. A computer prints 5,000 admit cards with the same quality from the first to the last. This shows its [1]adiligencebstoragecversatilitydautomation
6. Which memory loses its contents when the power goes off? [1]aROMbhard diskcRAMdpen drive
7. How many 4 MB photos can a 32 GB memory card hold, taking 1 GB = 1024 MB? [1]a8,000b8,192c4,096d1,024
8. The Nagarik App is an example of computers used in [1]aagriculturebgovernment servicescentertainmentdweather forecasting

Answers to 23.1

1. (b) — data become information only after processing.

2. (b) — comparing is a logical operation, done by the ALU.

3. (b) — Garbage In, Garbage Out: wrong input gives wrong output.

4. (c) — it senses touch (input) and shows pictures (output).

5. (a) — working on without tiring or losing quality is diligence.

6. (c) — RAM is temporary; the others keep data without power.

7. (b) — 32 × 1024 = 32,768 MB, and 32,768 ÷ 4 = 8,192.

8. (b) — citizens keep records and use government services in it.

23.2 History of Computer

Facts. Abacus: counting boards c. 2700 BC; on a suanpan a heaven bead = 5 and an earth bead = 1. Napier's bones (1617): multiplication. Slide rule (Oughtred, c. 1622): analog. Pascaline (Pascal, 1642): add and subtract, automatic carry. Stepped reckoner (Leibniz, 1673): all four operations. Jacquard loom (1804): punched cards. Babbage: Difference Engine (1822), Analytical Engine (1834) with mill (processor) and store (memory) — father of the computer; Ada Lovelace: first programmer (1843). Hollerith's tabulator: 1890 US census → IBM (1924). Mark I (1944): electromechanical. ABC (1942): first electronic digital. ENIAC (1946): first general-purpose electronic, 17,468 tubes. EDVAC: stored program. UNIVAC I (1951): first commercial computer in the USA. Nepal: IBM 1401 rented in 2028 BS for the census; ICL 2950/10 in 2038 BS.

1. On a Chinese abacus, the ones rod shows one heaven bead and three earth beads at the beam. The digit is [1]a4b8c6d15
2. Numbered rods that made multiplication easy were invented by [1]aBlaise PascalbJohn NapiercLeibnizdJacquard
3. The machine with a stepped drum that could add, subtract, multiply and divide was the [1]aPascalinebstepped reckonercabacusdslide rule
4. In the Analytical Engine, the "mill" did the work of today's [1]amemorybCPUcprinterdkeyboard
5. Punched cards were first used to control a [1]atabulating machinebloom for weavingcPascalinedslide rule
6. Which of these was electromechanical? [1]aENIACbHarvard Mark IcUNIVAC IdABC
7. The first commercial computer made in the USA was [1]aENIACbEDVACcUNIVAC IdMark I
8. Nepal's first computer, rented for the census of 2028 BS, was the [1]aICL 2950/10bIBM 1401cApple IIdUNIVAC I

Answers to 23.2

1. (b) — 5 + 1 + 1 + 1 = 8.

2. (b) — Napier's bones, 1617.

3. (b) — Leibniz's stepped reckoner, 1673; the Pascaline only added and subtracted.

4. (b) — the mill did the arithmetic; the store was the memory.

5. (b) — Jacquard's loom of 1804; Hollerith borrowed the idea later.

6. (b) — relays and a rotating shaft; the others were electronic.

7. (c) — the first was accepted by the US Census Bureau in 1951.

8. (b) — a second-generation computer rented at Rs 1,25,000 a month.

23.3 Generations of Computer

Facts. A generation is a stage marked by a new main component. 1st (1946–1958): vacuum tubes, machine language, milliseconds — ENIAC, UNIVAC I. 2nd (1958–1964): transistors (Bell Labs, 1947), assembly, FORTRAN, COBOL, microseconds — IBM 1401. 3rd (1964–1975): integrated circuits (Kilby, 1958), keyboards and monitors, time-sharing, nanoseconds. 4th (1975–): microprocessors (Intel 4004, 1971, 2,300 transistors), PCs, GUI, Internet. 5th: artificial intelligence and parallel processing. VLSI = Very Large Scale Integration. Moore's law: transistors double about every two years.

1. The main component of second-generation computers was the [1]avacuum tubebtransistorcintegrated circuitdmicroprocessor
2. ENIAC belongs to the [1]afirst generationbsecond generationcthird generationdfourth generation
3. Many transistors, resistors and capacitors made on one small piece of silicon form [1]aa vacuum tubeban integrated circuitca relayda punched card
4. The Intel 4004 of 1971 was the first [1]atransistorbintegrated circuitcmicroprocessordsupercomputer
5. Operations measured in microseconds are typical of the [1]afirst generationbsecond generationcthird generationdfifth generation
6. Understanding natural language and learning from data are aims of the [1]asecond generationbthird generationcfourth generationdfifth generation
7. VLSI stands for [1]aVery Large Scale IntegrationbVery Long Silicon InstructioncVisual Large Scale InterfacedVery Low Speed Integration
8. A chip has 1 million transistors. If the number doubles every two years, after four years it is expected to have [1]a2 millionb4 millionc8 milliond16 million

Answers to 23.3

1. (b) — transistors replaced vacuum tubes.

2. (a) — it used about 17,468 vacuum tubes.

3. (b) — an integrated circuit, or chip.

4. (c) — a whole CPU on one chip.

5. (b) — 1st milliseconds, 2nd microseconds, 3rd nanoseconds.

6. (d) — the fifth generation is about AI.

7. (a) — Very Large Scale Integration.

8. (b) — four years is two doublings: 1 → 2 → 4 million.

23.4 Types of Computer

Facts. Analog computers measure continuous data (speedometer with a needle, mercury thermometer, slide rule); digital computers count discrete data in 0s and 1s; hybrid computers do both (ECG, ICU monitor, petrol-pump dispenser). By size: supercomputer (fastest, measured in FLOPS; weather, research), mainframe (thousands of users; banks, airlines), minicomputer (tens to hundreds of users; PDP-11), microcomputer (one user, microprocessor). Microcomputers: desktop, laptop, tablet, smartphone, workstation (3D design, video). General-purpose computers run many programs; special-purpose (embedded) ones do one job.

1. A car's speedometer with a moving needle works as [1]aa digital computerban analog computerca hybrid computerda mainframe
2. A petrol-pump dispenser measures the flow of fuel and shows litres and rupees as numbers. It is [1]aanalogbdigitalchybridda supercomputer
3. The speed of a supercomputer is measured in [1]abpsbFLOPScdpidrpm
4. A bank's central computer that serves thousands of users at once is a [1]amicrocomputerbminicomputercmainframedanalog computer
5. An architect needs one powerful computer for 3D models. The best choice is a [1]aworkstationbtabletcmainframedembedded computer
6. The computer inside a washing machine is [1]ageneral-purposebspecial-purposeca supercomputerda mainframe
7. Forecasting the monsoon over South Asia needs a [1]asmartphonebsupercomputercminicomputerdanalog computer
8. A smartphone is a kind of [1]amainframebmicrocomputercanalog computerdminicomputer

Answers to 23.4

1. (b) — the needle moves smoothly; it measures.

2. (c) — analog measuring, digital calculating.

3. (b) — floating-point operations per second.

4. (c) — mainframes serve thousands of users reliably.

5. (a) — a fast single-user machine with a strong graphics card.

6. (b) — it does one job all its life (an embedded system).

7. (b) — huge parallel calculations need a supercomputer.

8. (b) — one user, one microprocessor.

23.5 Computer Software

Facts. System software runs the computer: operating system, device drivers (one per device), utility programs (antivirus, backup, compression, disk cleanup) and language processors (assembler; compiler — whole program at once; interpreter — line by line, stops at the first error). Application software does the user's work: packaged (made for many users — Word, Chrome, VLC) or tailor-made (for one organisation). Licences: proprietary (buy; code secret), freeware (free; code secret), shareware (free trial, then pay), open source (code open to change and share). Remove programs with Uninstall.

1. A program that lets the operating system control a scanner is a [1]autilitybdevice driverccompilerdgame
2. 7-Zip, which compresses files, is [1]aapplication softwarebutility softwarecan operating systemda device driver
3. A translator that runs a program one line at a time and stops at the first error is [1]aa compilerban interpretercan assemblerda driver
4. Software written for one hospital's own billing and records is [1]apackagedbtailor-madecfreewaredshareware
5. Software that may be used free for 30 days and must then be bought is [1]afreewarebsharewarecopen sourcedfirmware
6. Software whose source code anyone may read, change and share is [1]aproprietarybfreewarecopen sourcedshareware
7. Which of these is proprietary software? [1]aLibreOfficebLinuxcMicrosoft WindowsdFirefox
8. The safe way to remove a program from Windows 11 is to [1]adelete its desktop iconbuse Settings → Apps → Installed apps → Uninstallcdelete its folderdempty the Recycle Bin

Answers to 23.5

1. (b) — each device needs its own driver.

2. (b) — it maintains files, so it is a utility.

3. (b) — an interpreter works line by line.

4. (b) — made for one organisation's own needs.

5. (b) — try before you buy.

6. (c) — open source.

7. (c) — Windows must be licensed; the others are open source.

8. (b) — deleting icons or folders leaves the program or breaks it.

23.6 Operating System

Facts. The OS manages hardware and software and gives the user interface: process (multitasking), memory, file and device management, security, user interface. Single-user vs multi-user; CUI (typed commands — MS-DOS, Linux terminal) vs GUI (windows, icons, menus); desktop (Windows, macOS, Linux) vs mobile (Android, iOS). Linux: Linus Torvalds, 1991, open source; Android: Google, built on Linux. Dialog box: option button chooses one, check boxes several. Path: D:\School\Grade 8\file.docx. Copy: Ctrl + C, Ctrl + V; move: Ctrl + X, Ctrl + V; rename: F2. Shift + Delete and pen-drive deletions skip the Recycle Bin. Settings: Win + I; Nepal's time zone UTC+05:45.

1. Running a song while typing in Word is handled by the OS's [1]afile managementbprocess managementcsecurityddevice management
2. MS-DOS has [1]aa GUIba CUIca touch interfaceda voice interface
3. Linux was created by [1]aBill GatesbLinus TorvaldscSteve JobsdTim Berners-Lee
4. In a dialog box, the control that allows only one choice from a group is the [1]acheck boxboption buttonctext boxdspin box
5. For the file D:\School\Grade 8\notes.txt, the folder that directly contains it is [1]aD:bSchoolcGrade 8dnotes
6. Pressing Ctrl + X and then Ctrl + V on a file [1]acopies itbmoves itcrenames itddeletes it
7. A file deleted from a pen drive [1]agoes to the Recycle Binbis deleted permanentlycmoves to Documentsdis hidden
8. The shortcut that opens Windows Settings is [1]aWin + EbWin + IcWin + DdAlt + F4

Answers to 23.6

1. (b) — sharing the CPU among programs is process management.

2. (b) — commands are typed.

3. (b) — in 1991, as open source.

4. (b) — option (radio) buttons; check boxes allow several.

5. (c) — the last folder before the file name.

6. (b) — cut and paste moves.

7. (b) — removable drives have no Recycle Bin.

8. (b) — Win + E opens File Explorer, Win + D the desktop.

23.7 Word Processing

Facts. Word processors: Microsoft Word (.docx), LibreOffice Writer (.odt), Google Docs. Save Ctrl + S; Save As F12 (a new copy); Print Ctrl + P (pages 1-3, 6); Undo Ctrl + Z, Redo Ctrl + Y; Cut, Copy, Paste Ctrl + X, C, V; Find Ctrl + F, Replace Ctrl + H; spelling F7; Bold, Italic, Underline Ctrl + B, I, U; Left, Centre, Right, Justify Ctrl + L, E, R, J. Header at the top, footer at the bottom; Insert → Page Number. Table cells = rows × columns; merging k cells into one removes k − 1. Wrap Text: In Line, Square, Tight, Top and Bottom, Behind, In Front. WordArt (Writer: Fontwork). Mail merge (Mailings tab) = main document + data source → one copy per row.

1. Which of these is not a word processor? [1]aMicrosoft WordbLibreOffice WritercGoogle DocsdMicrosoft Excel
2. Ctrl + J applies [1]ajustified alignmentbboldca new pagedunderline
3. To keep the original file and save a changed copy under a new name, use [1]aSavebSave AscPrintdClose
4. Printing with Pages: 3-5, 8 prints how many pages of each copy? [1]a3b4c5d8
5. Text that repeats at the bottom of every page is the [1]aheaderbfootercmargindcaption
6. A table has 4 columns and 5 rows. After the 4 cells of the top row are merged, it has [1]a17 cellsb20 cellsc16 cellsd19 cells
7. The Start Mail Merge command is on the [1]aInsert tabbMailings tabcReferences tabdReview tab
8. Text flows around the rectangular box of a picture with the wrapping option [1]aIn Line with TextbSquarecBehind TextdTop and Bottom

Answers to 23.7

1. (d) — Excel is a spreadsheet.

2. (a) — L, E, R, J are left, centre, right, justify.

3. (b) — Save As makes a new copy; Save overwrites.

4. (b) — pages 3, 4, 5 and 8.

5. (b) — the footer; the header is at the top.

6. (a) — 4 × 5 = 20, and merging 4 cells into 1 leaves 20 − 3 = 17.

7. (b) — Mailings → Start Mail Merge.

8. (b) — Square wraps around the box; Tight follows the outline.

23.8 Spreadsheet Software

Facts. A workbook holds worksheets; a cell address is column + row (C5); a range B2:E6 has columns × rows cells. Formulas begin with =; brackets first, then ^, then * and /, then + and -. Relative references (B2) change when copied; absolute ones ($B$1) do not. SUM, AVERAGE, MAX, MIN, COUNT (numbers only), IF(condition, if_true, if_false). ##### means the column is too narrow. Sort reorders rows; filter hides rows that do not match. Charts: column and bar compare items, line shows change over time, pie shows parts of a whole (angle = share × 360°).

1. How many cells are in the range A2:C6? [1]a10b12c15d18
2. The result of =20-8/4 is [1]a3b18c12d2
3. A1:A4 hold 10, 15, 20 and 35. The result of =AVERAGE(A1:A4) is [1]a20b80c35d4
4. B1:B5 hold 12, Absent, 9, 15 and 8. The result of =COUNT(B1:B5) is [1]a5b4c44d1
5. C2 holds 40. The formula =IF(C2>=40,"Pass","Fail") shows [1]aPassbFailcTRUEd40
6. The formula =B2*$E$1 in C2 is copied to C3. In C3 it becomes [1]a=B3*$E$1b=B3*$E$2c=B2*$E$1d=C3*$F$1
7. To show only the rows in which Science is 60 or more, use [1]aSortbFiltercMerge & CenterdAutoFill
8. The best chart for Pokhara's temperature in each month of a year is a [1]apie chartbline chartctabledWordArt
9. A cell shows #####. The reason is that [1]athe formula is wrongbthe column is too narrowca number is divided by zeroda function is misspelled
10. In a pie chart of a family's spending of Rs 24,000, the slice for Rs 6,000 has an angle of [1]a60°b90°c25°d120°

Answers to 23.8

1. (c) — 3 columns (A, B, C) × 5 rows (2 to 6) = 15.

2. (b) — 8 ÷ 4 = 2 first, then 20 − 2 = 18.

3. (a) — (10 + 15 + 20 + 35) ÷ 4 = 80 ÷ 4 = 20.

4. (b) — COUNT ignores the text "Absent".

5. (a) — 40 >= 40 is TRUE.

6. (a) — B2 moves down a row; $E$1 stays fixed.

7. (b) — a filter hides rows that do not match.

8. (b) — a line chart shows change over time.

9. (b) — widen the column to see the number.

10. (b) — 6,000 ÷ 24,000 = ¼, and ¼ × 360° = 90°.

23.9 Presentation Software

Facts. PowerPoint (.pptx), LibreOffice Impress (.odp), Google Slides. New slide Ctrl + M; layouts arrange placeholders; a theme designs all slides. A transition works between slides; an animation works on objects — entrance (green), emphasis (yellow), exit (red), motion paths; starts On Click, With Previous or After Previous. Views: Normal, Outline, Slide Sorter, Notes Page, Reading View, Slide Show. The slide master changes every slide. F5 from the beginning, Shift + F5 from the current slide, Esc ends, B blacks the screen. 6 × 6 rule.

1. LibreOffice Impress saves presentations as [1]a.pptxb.odpc.odsd.odt
2. Ctrl + M in PowerPoint [1]aadds a new slidebopens the slide mastercmutes the sounddmoves a slide
3. The effect when one slide changes to the next is [1]aan animationba transitionca layoutda theme
4. In PowerPoint, entrance animations are marked in [1]agreenbyellowcreddblue
5. An animation that starts at the same time as the effect before it is set to [1]aOn ClickbWith PreviouscAfter PreviousdDelay
6. The view that shows small thumbnails of all slides for reordering them is [1]aNormalbSlide SortercNotes PagedReading View
7. Pressing Shift + F5 [1]astarts the show from the first slidebstarts the show from the current slidecends the showdblacks out the screen
8. An 8-slide self-running show moves on every 15 seconds. One run lasts [1]a1 minuteb2 minutesc23 secondsd2 minutes 30 seconds

Answers to 23.9

1. (b) — .odp, the OpenDocument presentation format.

2. (a) — Ctrl + M is New Slide in PowerPoint and Impress.

3. (b) — transitions work between slides.

4. (a) — green entrance, yellow emphasis, red exit.

5. (b) — With Previous runs together; After Previous waits.

6. (b) — Slide Sorter.

7. (b) — F5 starts from the first slide.

8. (b) — 8 × 15 = 120 seconds = 2 minutes.

23.10 Web Page Design

Facts. The WWW was invented by Tim Berners-Lee at CERN (1989–1991). A web page is one HTML document; a website is related pages under one domain; the home page is index.html. URL = protocol (https://) + domain name + path + file name. HTML: container tags (<p>…</p>) and empty tags (<br>, <hr>, <img>); attributes go in the opening tag. Structure: <html>, <head> with <title> (shown on the tab), <body> (shown in the window). <h1> is the largest heading, <h6> the smallest. <font> size 1–7, default 3. <ul type="square">, <ol type="a" start="3">, <li>. <img src alt width>. <a href>, mailto:, target="_blank". Tables: <tr>, <th>, <td>, colspan, rowspan.

1. The World Wide Web was invented by [1]aTim Berners-LeebCharles BabbagecBill GatesdLinus Torvalds
2. In https://www.ntc.net.np/plans.html, the protocol is [1]ahttpsbwwwcnet.npdplans.html
3. Which of these is an empty (unpaired) tag? [1]a<hr>b<h1>c<title>d<body>
4. The text inside <title> appears [1]aon the browser tabbas the top headingcat the foot of the pagednowhere
5. The smallest heading tag is [1]a<h1>b<h6>c<head>d<hr>
6. A list <ol type="a" start="3"> with two items numbers them [1]aa, bbc, dc3, 4diii, iv
7. The attribute of <img> whose text is shown when the picture cannot load is [1]asrcbaltchrefdwidth
8. Clicking <a href="mailto:info@school.edu.np">Write to us</a> [1]aopens a web pagebopens a new email messagecdownloads a filedshows a picture
9. A table cell that stretches down over two rows uses [1]acolspan="2"browspan="2"ccellspacing="2"dborder="2"
10. The default size of text in the <font> tag is [1]a1b3c5d7

Answers to 23.10

1. (a) — at CERN, 1989–1991.

2. (a) — https is the protocol; www.ntc.net.np is the domain name.

3. (a) — <hr> has no closing tag.

4. (a) — the title belongs to the head and shows on the tab.

5. (b) — <h1> is the largest, <h6> the smallest.

6. (b) — small letters starting from the third, c.

7. (b) — alt is the alternative text.

8. (b) — mailto: opens the email program.

9. (b) — rowspan spans rows; colspan spans columns.

10. (b) — sizes run from 1 to 7 and 3 is the default.

23.11 Information and Communication Technology

Facts. ICT is the use of computers, telecommunication equipment, networks and software to collect, store, process, send and receive information; its components are hardware, software, data, network, people and procedures. A geostationary satellite orbits at about 35,786 km. Nepal: Radio Nepal 1951, NTV 1985, e-mail 1994, first ISP 1995, GSM mobile 1999, 4G 2017, NepaliSat-1 2019, Nagarik App 2021. E-mail: To, Cc, Bcc (hidden copies), attachment. E-governance: G2C, G2B, G2G. Never share an OTP or MPIN. The digital divide is the gap between those with devices, Internet and skills and those without.

1. ICT stands for [1]aInformation and Communication TechnologybInternet and Computer ToolscInformation and Computer TypingdInternational Communication Television
2. The rules and steps for using an ICT system correctly and safely form its [1]aproceduresbhardwarecnetworkddata
3. A geostationary satellite orbits the Earth at a height of about [1]a350 kmb3,579 kmc35,786 kmd357,860 km
4. Nepal's first satellite, NepaliSat-1, was launched in [1]a2009b2017c2019d2021
5. To send a copy of an e-mail without the other receivers seeing that address, put it in [1]aTobCccBccdSubject
6. A citizen renewing a document through a government website is an example of [1]aG2GbG2BcG2CdB2B
7. A caller says he is from your bank and asks for the OTP sent to your phone. You should [1]atell him quicklybnever share itcshare half of itde-mail it
8. The gap between people who have devices, the Internet and the skill to use them and those who do not is the [1]adigital dividebbandwidthce-governancednetiquette

Answers to 23.11

1. (a) — Information and Communication Technology.

2. (a) — procedures are the rules and steps people follow.

3. (c) — about 35,786 km above the equator.

4. (c) — launched in 2019.

5. (c) — blind carbon copy.

6. (c) — government to citizen.

7. (b) — banks never ask for an OTP; it is a fraud.

8. (a) — the digital divide.

23.12 Computer Ethics and Cyber Law

Facts. Computer ethics are moral rules for using computers; the Ten Commandments were written by the Computer Ethics Institute (1992). Cyber crimes: hacking, phishing (fake messages that steal details), cyber bullying, identity theft, software piracy, online fraud. Intellectual property: copyright (in Nepal the author's life plus 50 years — Copyright Act, 2059), patents, trademarks; plagiarism is using another's work without credit. Nepal's cyber law: the Electronic Transactions Act, 2063; unauthorised access can bring up to Rs 2 lakh, 3 years or both. Report to the Cyber Bureau of Nepal Police. Your digital footprint is the trail you leave online.

1. The Ten Commandments of Computer Ethics were written by [1]athe Computer Ethics Institutebthe National Examinations BoardcMicrosoftdthe United Nations
2. A fake e-mail that looks like it comes from a bank and asks for your password is [1]ahackingbphishingcplagiarismdcyber bullying
3. Copying an essay from a website and handing it in as your own work is [1]apiracybplagiarismchackingdspam
4. Nepal's cyber law is the [1]aCopyright Act, 2059bElectronic Transactions Act, 2063cInformation Technology Policy, 2057dTelecommunications Act, 2053
5. In Nepal, the copyright of a book lasts for [1]a10 yearsbthe author's life plus 50 yearsc25 yearsdever
6. Under the Electronic Transactions Act, entering another person's computer account without permission can be punished with up to [1]aRs 2 lakh, 3 years in prison, or bothba Rs 500 fine onlyca warning onlyd20 years in prison
7. In Nepal, cyber crimes are reported to the [1]aCyber Bureau of Nepal PolicebNational Examinations BoardcNepal TelecomdCurriculum Development Centre
8. The record of everything you post, search and share online is your [1]adigital footprintbbandwidthcIP addressdavatar

Answers to 23.12

1. (a) — in 1992.

2. (b) — phishing "fishes" for passwords with fake messages.

3. (b) — plagiarism; piracy is copying software or media.

4. (b) — the Electronic Transactions Act, 2063.

5. (b) — life plus 50 years under the Copyright Act, 2059.

6. (a) — unauthorised access is an offence under the Act.

7. (a) — the Cyber Bureau handles cyber crime.

8. (a) — your digital footprint.

23.13 Computer Virus

Facts. A virus attaches itself to files and copies itself when they run; malware is the general name. Creeper (1971), Brain (1986, from Lahore, the first PC virus), Morris worm (1988), ILOVEYOU (2000), WannaCry (2017). Types: virus (needs a host), worm (spreads by itself over networks), Trojan horse (disguised as useful software), spyware (watches secretly; keyloggers), adware (unwanted adverts), ransomware (locks files for money). Antivirus detects, cleans, quarantines or deletes malware and must be updated — Microsoft Defender, Avast, Kaspersky. 3-2-1 backup: three copies, on two kinds of media, one kept off-site.

1. Malware that spreads by itself across a network without needing a host file is a [1]avirusbwormcadwaredTrojan horse
2. A free "game" that secretly opens the computer to an attacker is a [1]aTrojan horsebwormcfirewallddriver
3. Malware that locks your files and demands money to unlock them is [1]aspywarebransomwarecadwareda boot sector virus
4. Brain, the first virus for PCs (1986), came from [1]aLahorebKathmanducDelhidLondon
5. A keylogger, which records everything you type, is a kind of [1]aspywarebantiviruscfirewalldadware
6. Which of these is antivirus software? [1]aMicrosoft DefenderbWinRARcMicrosoft ExceldVLC
7. Moving a suspicious file to a locked, safe area so it cannot run is called [1]aquarantinebdefragmentingccompressingdformatting
8. The 3-2-1 backup rule is three copies, on two kinds of media, with [1]aone copy off-sitebone copy hiddencone copy printeddone copy compressed

Answers to 23.13

1. (b) — a worm copies itself over networks by itself.

2. (a) — it hides inside something that looks useful.

3. (b) — ransomware, e.g. WannaCry (2017).

4. (a) — written in Lahore, Pakistan.

5. (a) — it spies on the user.

6. (a) — the antivirus built into Windows.

7. (a) — quarantine isolates the file.

8. (a) — one copy away from home (or in the cloud) survives fire or theft.

23.14 Computer Network

Facts. A network joins two or more computers to share data, hardware and an Internet connection. Hub: copies data to all ports; switch: sends only to the destination port (by MAC address, 48 bits); router: joins different networks (by IP address); modem: digital ↔ analog. UTP cable uses RJ-45 plugs (100 m); optical fibre carries light. LAN (a building), MAN (a city), WAN (a country or the world), PAN (about 10 m). Topologies: bus (one backbone), ring (a loop), star (central switch; if it fails, all stop). The Internet uses TCP/IP and packets. Speed in bits: Mbps ÷ 8 = MB per second.

1. The device that sends data only to the port of the computer it is meant for is a [1]ahubbswitchcmodemdrepeater
2. The device that joins a school's LAN to the Internet using IP addresses is a [1]arouterbhubcNICdprinter
3. A MAC address is [1]a32 bits longb48 bits longc64 bits longd128 bits long
4. The plug on a UTP network cable is [1]aRJ-45bBNCcUSB-CdHDMI
5. A network inside one school building is a [1]aPANbLANcMANdWAN
6. In a star topology, if the central switch fails [1]aonly one computer stopsbthe whole network stopscnothing changesdthe speed doubles
7. A 100 Mbps connection can download at most [1]a100 MB per secondb12.5 MB per secondc800 MB per secondd8 MB per second
8. The basic set of rules that every computer on the Internet follows is [1]aTCP/IPbHTMLcICTdGUI

Answers to 23.14

1. (b) — a switch reads MAC addresses; a hub copies to all ports.

2. (a) — routers join different networks.

3. (b) — 48 bits, written as 12 hexadecimal digits.

4. (a) — RJ-45; BNC is for coaxial cable.

5. (b) — a local area network.

6. (b) — every computer depends on the centre.

7. (b) — 100 ÷ 8 = 12.5 megabytes per second.

8. (a) — Transmission Control Protocol / Internet Protocol.

23.15 Number System

Facts. Base (radix) = number of digits; largest digit = base − 1. Binary (base 2: 0, 1), octal (8: 0–7), decimal (10), hexadecimal (16: 0–9, A–F with A = 10 … F = 15). Decimal → base: divide repeatedly, read the remainders from the bottom up. Base → decimal: multiply each digit by its place value (\text{base}^0, \text{base}^1, …) and add. Binary → octal / hex: groups of 3 / 4 bits from the right. Memory: 4 bits = nibble, 8 bits = byte, 1 KB = 1024 bytes, 1 MB = 1024 KB, 1 GB = 1024 MB.

1. The base of the hexadecimal number system is [1]a2b8c10d16
2. (45)_{10} in binary is [1]a(101101)_2b(110101)_2c(101011)_2d(100101)_2
3. (110101)_2 in decimal is [1]a53b45c35d52
4. (157)_8 in decimal is [1]a111b157c117d109
5. (2F)_{16} in decimal is [1]a32b47c215d45
6. (11010110)_2 in octal is [1]a(326)_8b(652)_8c(316)_8d(236)_8
7. (11010110)_2 in hexadecimal is [1]a(D6)_{16}b(6D)_{16}c(C6)_{16}d(D5)_{16}
8. (A3)_{16} in binary is [1]a(10100011)_2b(10110011)_2c(1010011)_2d(11000011)_2
9. The largest digit used in the octal system is [1]a7b8c9dF
10. 4 GB is equal to [1]a4,000 MBb4,096 MBc1,024 MBd4,096 KB

Answers to 23.15

1. (d) — sixteen digits, 0–9 and A–F.

2. (a) — 45 = 32 + 8 + 4 + 1, so 101101.

3. (a) — 32 + 16 + 4 + 1 = 53.

4. (a) — 1 × 64 + 5 × 8 + 7 = 64 + 40 + 7 = 111.

5. (b) — 2 × 16 + 15 = 47.

6. (a) — 011 010 110 gives 3, 2, 6.

7. (a) — 1101 0110 gives D (13) and 6.

8. (a) — A = 1010 and 3 = 0011.

9. (a) — base 8 uses 0 to 7.

10. (b) — 4 × 1024 = 4,096 MB.

23.16 Computer Graphics

Facts. Raster (bitmap) pictures are grids of pixels and blur or pixelate when enlarged; vector pictures store shapes as numbers and stay sharp at any size. Colour depth n bits gives 2^n colours (8-bit = 256; 24-bit = 16,777,216); each pixel mixes red, green and blue (0–255 each). Uncompressed size = width × height × bits ÷ 8 bytes. Paint and GIMP edit raster pictures; Inkscape draws vectors (SVG); Canva uses online templates. BMP uncompressed; JPEG lossy, small, for photos; PNG lossless with transparency; GIF 256 colours, simple animation; SVG vector.

1. A picture made of a grid of tiny coloured squares is [1]aa raster graphicba vector graphiccan animationda font
2. A school logo that must stay sharp on a badge and on a banner should be made as [1]aa raster graphicba vector graphicca BMP fileda JPEG file
3. With a colour depth of 8 bits, a pixel can show [1]a8 coloursb64 coloursc256 coloursd16,777,216 colours
4. The uncompressed size of an 800 × 600 picture with 24-bit colour is [1]a480,000 bytesb1,440,000 bytesc11,520,000 bytesd14,400 bytes
5. The free vector-drawing program that saves SVG files is [1]aPaintbGIMPcInkscapedExcel
6. For a photograph on a website, where small file size matters most, the usual format is [1]aBMPbJPEGcSVGdTXT
7. The format that keeps every detail and allows a transparent background is [1]aPNGbJPEGcBMPdMP3
8. A small moving sticker with few colours is usually a [1]aGIF filebBMP filecDOCX filedXLSX file

Answers to 23.16

1. (a) — pixels make a raster (bitmap) picture.

2. (b) — vectors scale without losing sharpness.

3. (c) — 2^8 = 256.

4. (b) — 800 × 600 × 24 ÷ 8 = 1,440,000 bytes.

5. (c) — Inkscape; GIMP and Paint are raster editors.

6. (b) — JPEG compresses photos strongly (with some loss).

7. (a) — PNG is lossless and supports transparency.

8. (a) — GIF supports simple animation in up to 256 colours.

23.17 Multimedia

Facts. Multimedia combines two or more media: text, graphics, audio, video and animation. Video is recorded from real life; animation is drawn or computer-made pictures shown quickly (about 12–30 a second). Linear multimedia plays in a fixed order (a film); interactive multimedia responds to the user (E-Paath, games). Hardware: microphone, webcam, scanner, speakers, projector, sound and graphics cards. Software: VLC, Audacity (audio), OpenShot and Kdenlive (video), Blender (animation). Uncompressed sound = samples per second × bits × channels × seconds ÷ 8 bytes. Uses in education, entertainment, business and health.

1. Which of these is not an element of multimedia? [1]atextbaudiocanimationdelectricity
2. Pictures drawn one by one and shown quickly so that they seem to move form [1]aan animationba video recordingctextdaudio
3. A film watched from beginning to end without any choices is [1]alinear multimediabinteractive multimediaca raster graphicda vector graphic
4. An E-Paath lesson in which you click to answer and choose what to see next is [1]alinearbinteractivecanalogdprinted
5. The free program for recording and editing sound is [1]aAudacitybInkscapecExceldPaint
6. One minute of uncompressed CD-quality stereo sound (44,100 samples a second, 16 bits, 2 channels) takes about [1]a1 MBb10 MBc100 MBd1 GB
7. To play sound, a computer needs [1]aa sound card and speakersba scannerca webcamda keyboard
8. Telemedicine and medical images are uses of multimedia in [1]ahealthbfarming onlycbanking onlydsports only

Answers to 23.17

1. (d) — the five elements are text, graphics, audio, video and animation.

2. (a) — animation; video is recorded from real life.

3. (a) — linear: a fixed order.

4. (b) — interactive: it responds to the user.

5. (a) — Audacity is a free audio editor.

6. (b) — 44,100 × 16 × 2 × 60 ÷ 8 = 10,584,000 bytes, about 10 MB.

7. (a) — the sound card makes the signal; speakers play it.

8. (a) — health care.

23.18 Program Design Tools

Facts. A program is a set of instructions; the program development life cycle is problem analysis (input, process, output) → design → coding → testing and debugging → documentation → implementation and maintenance. An algorithm is a finite set of clear steps from Start to Stop, with input, output, definiteness, finiteness and effectiveness. Flowchart symbols: oval (start/stop), parallelogram (input/output), rectangle (process), diamond (decision), arrows (flow), circle (connector). Every algorithm uses sequence, selection and repetition. Pseudocode is structured English (INPUT, PRINT, IF … ENDIF, WHILE … ENDWHILE). A trace table is a dry run.

1. The flowchart symbol for a decision is the [1]adiamondbrectanglecovaldparallelogram
2. The flowchart symbol for input and output is the [1]aparallelogrambdiamondccircledoval
3. Start and Stop are drawn in [1]aan ovalba rectangleca diamonddan arrow
4. The property that an algorithm must end after a fixed number of steps is [1]adefinitenessbfinitenessceffectivenessdinput
5. The first step of program development is [1]acodingbproblem analysisctestingddocumentation
6. "Repeat these steps until the counter reaches 10" is an example of [1]asequencebselectioncrepetitionddocumentation
7. Structured English with keywords such as IF … ENDIF is called [1]apseudocodebmachine codeca flowchartdHTML
8. An algorithm sets N = 1, then repeats "PRINT N × 2; N = N + 1" while N ≤ 4. It prints [1]a2, 4, 6, 8b1, 2, 3, 4c2, 4, 6, 8, 10d1, 3, 5, 7

Answers to 23.18

1. (a) — a diamond has two labelled exits, yes and no.

2. (a) — parallelogram.

3. (a) — the oval terminal symbol.

4. (b) — finiteness.

5. (b) — first understand the input, process and output.

6. (c) — a loop repeats steps.

7. (a) — pseudocode.

8. (a) — N takes 1, 2, 3, 4, printing 2, 4, 6, 8; at N = 5 the loop stops.

23.19 Fundamentals of Computer Programming

Facts. Machine language is binary and runs directly; assembly language uses mnemonics (MOV, ADD) and needs an assembler; high-level languages (QBASIC, Python, C, Java) are English-like. A compiler translates the whole program; an interpreter one line at a time. Errors: syntax (breaking the language's rules), run-time (an impossible operation while running, e.g. division by zero), logical (wrong method, wrong answer, no message). Debugging finds and corrects errors. QBASIC (Microsoft, 1991), Python (Guido van Rossum, 1991), C (Dennis Ritchie, 1972), Java (James Gosling, 1995). QBASIC types: % integer, & long, ! single (default), # double, $ string.

1. The language written only in 0s and 1s is [1]amachine languagebassembly languagecPythondQBASIC
2. MOV and ADD are mnemonics of [1]aassembly languagebHTMLcPythondmachine language
3. Dividing a number by zero while a program is running causes [1]aa syntax errorba run-time errorca logical errordno error
4. A program adds two numbers when it should multiply them; it runs and gives wrong answers with no message. This is [1]aa syntax errorba run-time errorca logical errorda compile error
5. The C language was developed by [1]aDennis RitchiebGuido van RossumcJames GoslingdTim Berners-Lee
6. Python was created by [1]aGuido van RossumbDennis RitchiecJames GoslingdLinus Torvalds
7. In QBASIC, the variable N$ holds [1]aa stringban integerca double-precision numberda long integer
8. Finding and correcting the errors in a program is called [1]adebuggingbcompilingccodingddocumenting

Answers to 23.19

1. (a) — the only language the CPU runs directly.

2. (a) — mnemonics are short codes of assembly language.

3. (b) — it fails only while running.

4. (c) — the logic is wrong, so the answer is wrong.

5. (a) — Dennis Ritchie, 1972.

6. (a) — Guido van Rossum, 1991.

7. (a) — the $ sign marks a string variable.

8. (a) — debugging.

23.20 Computer Programming using QBASIC

Facts. CLS clears the screen, REM writes a remark, LET assigns, INPUT reads, PRINT displays (; joins, , jumps to the next zone), END ends; Shift + F5 runs, F8 steps, F9 sets a breakpoint. Operators: ^, * /, \ (integer division), MOD (remainder), + -; relational results: true = −1, false = 0. Functions: SQR, ABS, INT (next lower whole number), FIX (drops the decimal part), LEN, LEFT$, RIGHT$, MID$, UCASE$, LCASE$. FOR … NEXT with STEP; WHILE … WEND and DO WHILE … LOOP test first; DO … LOOP UNTIL tests last and runs at least once.

1. The statement that clears the screen is [1]aCLSbCLEARcREMdEND
2. The value of 17 MOD 5 is [1]a2b3c3.4d12
3. The value of 17 \ 5 is [1]a3b2c3.4d85
4. LEN("NEPAL") returns [1]a4b5c6dNEPAL
5. MID$("COMPUTER", 4, 3) returns [1]aPUTbMPUcUTEdCOM
6. How many times does the body of FOR I = 1 TO 10 STEP 3 run? [1]a3b4c10d30
7. The loop that tests its condition at the end, and so always runs at least once, is [1]aDO … LOOP UNTILbWHILE … WENDcDO WHILE … LOOPdnone of them
8. INT(-4.7) returns [1]a−4b−5c4d−4.7
9. The key that runs a QBASIC program is [1]aF5 alonebShift + F5cCtrl + SdF8
10. PRINT 5 > 3 displays [1]aTRUEb1c−1dYES

Answers to 23.20

1. (a) — CLS clears the output screen.

2. (a) — 17 = 3 × 5 + 2; MOD gives the remainder.

3. (a) — integer division drops the remainder.

4. (b) — N, E, P, A, L: five characters.

5. (a) — three characters starting at the 4th: P, U, T.

6. (b) — I takes 1, 4, 7, 10.

7. (a) — UNTIL at the bottom is checked after the body has run.

8. (b) — INT goes down to the next lower whole number; FIX(−4.7) would give −4.

9. (b) — Shift + F5; F8 steps one line at a time.

10. (c) — QBASIC shows true as −1.

Chapter summary

• Fundamentals, history and generations: data → process → information; CU directs, ALU calculates; GIGO; Pascal 1642, Leibniz 1673, Babbage (mill and store), Lovelace, Hollerith 1890, ENIAC 1946, UNIVAC I 1951; IBM 1401 in Nepal (2028 BS); tube → transistor → IC → microprocessor → AI.
• Types, software and OS: analog measures, digital counts, hybrid does both; super > mainframe > mini > micro; system vs application software; compiler (whole) vs interpreter (line by line); proprietary, freeware, shareware, open source; CUI vs GUI; copy, move, Recycle Bin.
• Office software: Ctrl + S, F12, Ctrl + Z, Ctrl + H, Ctrl + J; header top, footer bottom; mail merge on Mailings; ranges are columns × rows; formulas start with =; $E$1 stays fixed; COUNT counts numbers; transitions between slides, animations on objects; F5 and Shift + F5.
• Web and society: URL = protocol + domain + path + file; <title> on the tab; <h1> largest; empty tags <br>, <hr>, <img>; alt, href, mailto:, colspan, rowspan; ICT, G2C, Bcc, OTP; phishing, plagiarism, ETA 2063; worm, Trojan, ransomware, quarantine.
• Networks, numbers and media: switch by MAC, router by IP; RJ-45; LAN/MAN/WAN; star; Mbps ÷ 8 = MB/s; read remainders upwards; groups of 3 (octal) and 4 (hex); 1 GB = 1024 MB; raster vs vector; 2^n colours; PNG, JPEG, GIF, SVG; linear vs interactive multimedia.
• Programming: oval, parallelogram, rectangle, diamond; sequence, selection, repetition; syntax, run-time and logical errors; \ quotient, MOD remainder, INT rounds down; FOR … STEP counts; DO … LOOP UNTIL runs at least once; true is −1.