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Punjab PSEB SS Computer Application study materials
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Punjab PSEB SS Computer Application practice questions

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Question 1Computer Science

In a spreadsheet, which symbol must a formula begin with so that the software treats the entry as a calculation rather than as text?

  1. #
  2. &
  3. = Correct answer.
  4. @

Explanation

A spreadsheet formula always starts with the equals sign, which signals that the following characters form an expression to be evaluated. Without it, entries such as SUM(A1:A5) are stored as ordinary text and no result is computed.

Question 2Computer Science

Which file extension is normally associated with a Microsoft Word document?

  1. XLSX
  2. DOCX Correct answer.
  3. PPTX
  4. PDF

Explanation

Word saves editable documents with the .docx extension in its modern default format. XLSX belongs to Excel workbooks and PPTX to PowerPoint presentations, while PDF is a portable fixed-layout format.

Question 3Computer Science

In a computer network, what does the abbreviation LAN stand for?

  1. Large Area Network
  2. Linked Access Node
  3. Local Area Network Correct answer.
  4. Logical Address Number

Explanation

LAN stands for Local Area Network, a network covering a limited area such as a school computer lab or a single building. It is contrasted with WAN, which spans large geographical distances.

Question 4Computer Science

Which of the following is an example of system software rather than application software?

  1. An operating system Correct answer.
  2. A spreadsheet program
  3. A photo editor
  4. A web browser

Explanation

System software manages hardware and provides a platform on which other programs run; an operating system is the primary example. Spreadsheets, browsers and photo editors are application software written to perform user tasks.

Question 5Computer Science

In a relational database table, what is a primary key?

  1. A field that may contain duplicate values
  2. A field whose value uniquely identifies each record Correct answer.
  3. A field used only to store numeric totals
  4. The first column created in the table

Explanation

A primary key is a field or combination of fields whose value is unique for every record and is never null, so each row can be identified unambiguously. Physical position in the table has no bearing on which field serves as the key.

Question 6Computer Science

Which keyboard shortcut is commonly used to copy the selected item in Windows applications?

  1. Ctrl + C Correct answer.
  2. Ctrl + Z
  3. Ctrl + X
  4. Ctrl + V

Explanation

Ctrl + C places a copy of the selected content on the clipboard while leaving the original in place. The related shortcuts Ctrl + X cuts and Ctrl + V pastes the clipboard contents.

Question 7Computer Science

Which number system uses only the digits 0 and 1 and is the basis of digital data representation?

  1. Binary Correct answer.
  2. Decimal
  3. Hexadecimal
  4. Octal

Explanation

The binary system has base 2 and therefore only two symbols, 0 and 1, which map directly onto the off and on states of digital circuits. Octal and hexadecimal are compact notations used by programmers but use more digits.

Question 8Computer Science

What is the main purpose of an email signature in a message?

  1. To compress attachments
  2. To append the sender's identifying details automatically Correct answer.
  3. To schedule delivery time
  4. To encrypt the message body

Explanation

An email signature is a block of text, often containing name, designation and contact details, that the client appends automatically at the end of outgoing messages. It carries no encryption, compression or scheduling function.

Question 9Computer Science

A student types =B2*C2 in cell D2 of a spreadsheet and then copies the formula down to D3. What formula appears in D3?

  1. =B3*C3 Correct answer.
  2. =B2*C3
  3. =B3*C2
  4. =B2*C2

Explanation

When a formula containing relative references is copied one row down, both row numbers increase by one, so B2 and C2 become B3 and C3. Absolute references would be needed if a reference had to stay fixed.

Question 10Computer Science

What is the decimal value of the binary number 1011?

  1. 11 Correct answer.
  2. 15
  3. 9
  4. 13

Explanation

Evaluating place values gives 1×8 + 0×4 + 1×2 + 1×1 = 11. Each position to the left doubles in weight, starting from 1 at the rightmost bit.

Question 11Computer Science

Which SQL clause is used to filter rows returned by a query based on a condition?

  1. GROUP BY
  2. ORDER BY
  3. HAVING
  4. WHERE Correct answer.

Explanation

The WHERE clause applies a condition to individual rows before grouping, so only rows satisfying it are returned. ORDER BY sorts results and GROUP BY forms groups, while HAVING filters groups after aggregation.

Question 12Computer Science

In a spreadsheet, which function returns the largest value in the range A1:A10?

  1. =SUM(A1:A10)
  2. =COUNT(A1:A10)
  3. =MIN(A1:A10)
  4. =MAX(A1:A10) Correct answer.

Explanation

The MAX function scans the given range and returns its highest numeric value. MIN returns the smallest, SUM adds the values and COUNT reports how many numeric entries exist.

Question 13Computer Science

Which device converts digital signals from a computer into analogue signals that can travel over a telephone line?

  1. Repeater
  2. Switch
  3. Router
  4. Modem Correct answer.

Explanation

A modem performs modulation and demodulation, converting digital data to analogue form for transmission and back again at the receiving end. Routers forward packets between networks and switches connect devices within a LAN.

Question 14Computer Science

What is the primary function of cache memory in a computer system?

  1. To store files permanently after shutdown
  2. To hold frequently used data close to the processor for fast access Correct answer.
  3. To back up data to an external drive
  4. To convert programs into machine code

Explanation

Cache is a small, high-speed memory placed between the CPU and main memory that keeps recently or frequently used instructions and data. This reduces the average time the processor waits for main memory.

Question 15Computer Science

A student wants the formula in cell E5 to always refer to the value in cell B1 when copied to other cells. Which reference should be used?

  1. $B1
  2. B1
  3. B$1
  4. $B$1 Correct answer.

Explanation

An absolute reference places a dollar sign before both the column letter and the row number, so neither part changes when the formula is copied. Mixed references fix only one component and still shift the other.

Question 16Computer Science

Which of the following is a valid IPv4 address?

  1. 192.168.1
  2. 192.168.1.256
  3. 192.168.1.10 Correct answer.
  4. 192.168.1.10.5

Explanation

An IPv4 address consists of four decimal octets separated by dots, and each octet must lie between 0 and 255. The address 192.168.1.10 satisfies both conditions.

Question 17Computer Science

In a database, which type of relationship exists when one record in table A can be linked to many records in table B, but each record in B links to only one record in A?

  1. One-to-one
  2. Zero-to-one
  3. Many-to-many
  4. One-to-many Correct answer.

Explanation

A one-to-many relationship links a single parent record to multiple child records while each child belongs to exactly one parent, as with a customer and their orders. A many-to-many relationship would allow several records on both sides.

Question 18Computer Science

Why is a compiler generally preferred over an interpreter for distributing commercial software?

  1. It translates the program line by line at run time
  2. It always uses less memory during execution
  3. It produces a standalone executable that runs without the source code Correct answer.
  4. It eliminates the need for any testing

Explanation

A compiler translates the entire source program into machine code in advance, producing an executable file that can be distributed without revealing the source. An interpreter translates and executes statements one at a time and requires the source to be present.

Question 19Computer Science

A school wants its computer lab to share one internet connection while keeping local traffic separate from outside networks. Which combination of devices best serves this purpose?

  1. A hub and a plotter
  2. A repeater and a scanner
  3. A modem and a printer
  4. A router and a switch Correct answer.

Explanation

The switch connects the lab computers into a local network and forwards frames between them, while the router joins that local network to the internet and directs traffic between the two. Peripheral devices such as printers and scanners do not perform these networking functions.

Question 20Computer Science

A student needs to submit a typed report containing text, a table and a chart. Which software category is most appropriate?

  1. Spreadsheet software
  2. Image editing software
  3. Presentation software
  4. Word processing software Correct answer.

Explanation

Word processing software is designed for composing documents that combine text with tables, images and charts arranged on pages. Spreadsheets suit calculations and presentations suit slide-based delivery, but neither is optimised for a multi-page written report.

Question 21Computer Science

A spreadsheet cell displays the error value #DIV/0!. What is the most likely cause?

  1. The formula contains a misspelled function name
  2. The column is too narrow to show the result
  3. The formula refers to a text value in a numeric operation
  4. The formula divides by a cell that is empty or contains zero Correct answer.

Explanation

The #DIV/0! error appears when a division operation has a divisor equal to zero, including a reference to a blank cell that is treated as zero. Correcting the divisor or guarding the formula with a condition clears the error.

Question 22Computer Science

A binary number has 8 bits. What is the largest unsigned decimal value it can represent?

  1. 128
  2. 512
  3. 256
  4. 255 Correct answer.

Explanation

With n bits the number of distinct patterns is 2^n, so 8 bits give 256 patterns. Counting from zero, the largest unsigned value is therefore 2^8 − 1, which equals 255.

Question 23Computer Science

A table stores student records and a separate table stores the subjects each student has chosen. Which design correctly models the many-to-many relationship between students and subjects?

  1. Create a linking table containing student and subject identifiers Correct answer.
  2. Merge both tables into a single table with repeated rows
  3. Add a subject column to the student table only
  4. Add a student column to the subject table only

Explanation

A many-to-many relationship cannot be represented by a single foreign key on either side, because each student may take several subjects and each subject may be taken by several students. A junction table holding both identifiers resolves it into two one-to-many relationships.

Question 24Computer Science

A program must repeatedly read input values until the user enters a sentinel value, then display a summary. Which control structure is most suitable for the input loop?

  1. A while loop tested before each iteration Correct answer.
  2. A definite for loop with a fixed count
  3. A nested function definition
  4. A single sequential statement block

Explanation

Because the number of inputs is unknown in advance, the loop must be controlled by a condition rather than a fixed count. A while loop checks the condition before each iteration and stops as soon as the sentinel value is read.

Question 25Computer Science

Two hosts on the same local network have been assigned the identical IPv4 address. What is the most likely consequence?

  1. The router will automatically double the bandwidth
  2. Both hosts will receive faster connections
  3. Address conflicts will disrupt communication for one or both hosts Correct answer.
  4. The network will convert the address to IPv6

Explanation

An IPv4 address must be unique within a network, so duplicate assignment causes an address conflict in which replies may be delivered to the wrong host and connectivity fails intermittently. Automatic conversion to IPv6 or increased bandwidth does not occur.

Question 26Computer Science

Which type of software is MS Windows an example of?

  1. Programming software
  2. System software Correct answer.
  3. Utility software
  4. Application software

Explanation

An operating system is system software because it manages hardware, memory, files and provides the platform on which other programs run. Application, utility and programming tools all run on top of that platform rather than providing it.

Question 27Computer Science

Which storage medium stores data using laser light and is typically read-only when supplied with software?

  1. Optical disc Correct answer.
  2. Magnetic tape
  3. Solid-state drive
  4. Hard disk drive

Explanation

Optical discs such as CD-ROM and DVD-ROM record data as pits and lands that are read by a laser beam. Pressed discs of this kind cannot be rewritten by the user, which is why they suit software distribution.

Question 28Computer Science

In a word processor, which feature is used to place the same text automatically at the bottom of every page of a report?

  1. Footnote
  2. Footer Correct answer.
  3. Text box
  4. Header

Explanation

A footer is a page region repeated at the bottom of each page, so page numbers or document titles entered there appear on every page automatically. A header does the same job at the top of the page.

Question 29Computer Science

What does the file extension .pptx indicate about a file?

  1. It is a spreadsheet workbook
  2. It is a presentation created in PowerPoint Correct answer.
  3. It is a plain text document
  4. It is a compressed archive

Explanation

The extension identifies the file type and the program that can open it; .pptx is the modern PowerPoint presentation format. Windows uses this extension to associate the file with the correct application.

Question 30Computer Science

Which key is held down with a letter key to type an uppercase letter on a standard keyboard?

  1. Tab
  2. Shift Correct answer.
  3. Ctrl
  4. Alt

Explanation

Shift is a modifier key: holding it while pressing a letter key produces the uppercase character shown on the key cap. Ctrl and Alt are also modifiers but are used for shortcuts rather than case change.

Question 31Computer Science

Which generation of computers is characterised by the use of integrated circuits?

  1. Fourth generation
  2. Third generation Correct answer.
  3. First generation
  4. Second generation

Explanation

Third-generation computers replaced discrete transistors with integrated circuits, which packed many components onto one chip and made machines smaller and more reliable. The fourth generation is associated with microprocessors.

Question 32Computer Science

Which protocol is used to transfer web pages between a web server and a browser?

  1. HTTP Correct answer.
  2. DNS
  3. FTP
  4. SMTP

Explanation

HTTP defines how a browser requests a web resource and how the server responds with the page content. FTP, SMTP and DNS serve file transfer, mail delivery and name resolution respectively.

Question 33Computer Science

In a relational database, which key uniquely identifies each record in a table?

  1. Primary key Correct answer.
  2. Candidate key
  3. Foreign key
  4. Composite key

Explanation

The primary key is the chosen field or field combination whose value is unique and never null for every row, so each record can be identified exactly. Other keys may also be unique but are not the one selected to identify rows.

Question 34Computer Science

A student wants the value 500 to appear in cell A1 as currency with two decimal places. Which number format should be applied?

  1. Number with 0 decimal places
  2. General
  3. Currency with 2 decimal places Correct answer.
  4. Percentage

Explanation

Currency format inserts the currency symbol and fixes the displayed decimal places, so the stored value 500 is shown as a monetary amount with two decimals. The underlying value does not change, only its display.

Question 35Computer Science

A cell contains the formula =IF(A1>=40,"Pass","Fail"). If A1 holds 40, what does the cell display?

  1. 40
  2. #VALUE!
  3. Pass Correct answer.
  4. Fail

Explanation

The IF function returns the first result when the logical test is true. Because the test uses the greater-than-or-equal operator, 40 satisfies A1>=40 and the text Pass is returned.

Question 36Computer Science

A student writes a paragraph and wants the first line of each paragraph indented while the rest stays flush. Which setting is used?

  1. First-line indent Correct answer.
  2. Justification
  3. Hanging indent
  4. Line spacing

Explanation

A first-line indent pushes only the opening line of a paragraph inward, which is the conventional way to mark a new paragraph. A hanging indent does the opposite by indenting all lines except the first.

Question 37Computer Science

Which conversion is performed by an analogue-to-digital converter in a computer system?

  1. Binary numbers to decimal numbers for display
  2. Compressed files to their original form
  3. Continuous physical signals to discrete numeric values Correct answer.
  4. Digital data to analogue signals for a speaker

Explanation

An ADC samples a continuously varying physical quantity such as sound and quantises each sample into a discrete number the computer can store. The reverse direction, numbers to a continuous signal, needs a DAC.

Question 38Computer Science

A user reports that a computer powers on but shows no image on the monitor, and the monitor's power light is on. Which step is the most appropriate first check?

  1. Verify the video cable connection and monitor input source Correct answer.
  2. Replace the hard disk
  3. Reinstall the operating system
  4. Run a full antivirus scan

Explanation

When the monitor has power but no picture, the fault usually lies in the signal path, so the cable and the selected input source should be checked first. This is a cheap, non-destructive test before any hardware replacement or software action.

Question 39Computer Science

A company wants employees to access shared files with different permission levels. Which type of network is most suitable for a single office building?

  1. PAN
  2. WAN
  3. LAN Correct answer.
  4. MAN

Explanation

A LAN connects devices within a limited area such as one building and supports central file servers with per-user permissions. Larger geographic scopes are handled by MAN and WAN technologies.

Question 40Computer Science

What is the main function of a web browser?

  1. To compile source code into machine code
  2. To request, interpret and display web resources Correct answer.
  3. To manage the file system of the computer
  4. To assign IP addresses to network devices

Explanation

A browser sends HTTP requests for web resources and renders the returned HTML, CSS and scripts into a viewable page. It acts as the client in the client-server model of the web.

Question 41Computer Science

Which of the following is an example of system software that translates a whole program before execution?

  1. Loader
  2. Editor
  3. Linker
  4. Compiler Correct answer.

Explanation

A compiler translates the complete source program into object code before the program runs, reporting errors in a batch. The linker and loader then combine and place that code into memory for execution.

Question 42Computer Science

A spreadsheet contains names in column A and marks in column B. Which formula counts how many students scored more than 75?

  1. =AVERAGEIF(B2:B20,">75")
  2. =SUM(B2:B20>75)
  3. =COUNTIF(B2:B20,">75") Correct answer.
  4. =COUNT(B2:B20)

Explanation

COUNTIF counts the cells in a range that satisfy a given criterion, so COUNTIF with the criterion ">75" returns the number of marks above 75. The comparison must be written as text inside quotes.

Question 43Computer Science

Which statement about RAM and ROM is correct?

  1. RAM retains its contents permanently after shutdown
  2. ROM can be written to as often as RAM during normal use
  3. RAM is volatile and holds programs currently in use Correct answer.
  4. ROM is volatile and loses its contents at power-off

Explanation

RAM is read-write volatile memory that holds the operating system and running programs while power is on. ROM is non-volatile and normally read-only, holding firmware such as the boot instructions.

Question 44Computer Science

A student types 25% into a cell and the cell displays 0.25. What has happened?

  1. The decimal separator has been changed
  2. The value has been converted to text
  3. The formula contains a circular reference
  4. The cell has been formatted as Percentage Correct answer.

Explanation

Percentage format stores the underlying fraction and displays it multiplied by 100 with a percent sign. Typing 25% therefore stores 0.25, which appears as 25% only when percentage formatting is active.

Question 45Computer Science

Which addressing mode is used when an instruction contains the operand itself rather than its address?

  1. Immediate addressing Correct answer.
  2. Register addressing
  3. Direct addressing
  4. Indirect addressing

Explanation

In immediate addressing the operand value is encoded directly in the instruction, so no memory fetch for the operand is needed. Direct and indirect modes supply an address or the address of an address instead.

Question 46Computer Science

A table of orders stores the customer name in every order row. Which problem does this design most directly cause?

  1. Faster query execution
  2. Automatic enforcement of referential integrity
  3. Loss of the primary key
  4. Data redundancy and update anomalies Correct answer.

Explanation

Repeating the customer name in every order row duplicates data, so a change of name must be made in many places and inconsistent copies can result. Normalisation removes this by storing the customer once and referring to it by key.

Question 47Computer Science

A recursive function has no base case. What is the most likely result when it is called?

  1. It runs until the call stack overflows Correct answer.
  2. It compiles with a syntax error
  3. It is converted automatically into a loop
  4. It returns zero immediately

Explanation

Each recursive call adds a frame to the call stack, and without a terminating base case the calls never stop, so the stack eventually overflows. Compilers generally do not reject such logic because it is syntactically valid.

Question 48Computer Science

A network uses the subnet mask 255.255.255.192. How many usable host addresses does each subnet provide?

  1. 62 Correct answer.
  2. 64
  3. 126
  4. 30

Explanation

The mask 255.255.255.192 borrows two bits for the subnet portion, leaving six host bits. Six host bits give 64 addresses, and subtracting the network and broadcast addresses leaves 62 usable hosts.

Question 49Computer Science

In a relational database, a foreign key value that matches no primary key in the referenced table violates which constraint?

  1. Domain integrity
  2. Referential integrity Correct answer.
  3. Key uniqueness
  4. Entity integrity

Explanation

Referential integrity requires every foreign key value to match an existing primary key value in the referenced table, or to be null where permitted. A dangling reference breaks that rule and is rejected by the DBMS.

Question 50Computer Science

A student creates a document in a word processor and saves it with the .docx extension. Which type of file has been created?

  1. A document file that stores formatting, images and layout information Correct answer.
  2. A text file containing only plain unformatted characters
  3. A compressed archive holding several files together
  4. An executable file that runs when double-clicked

Explanation

The .docx extension belongs to a word-processing document format, so the file stores text together with formatting, images, tables and page layout rather than raw characters alone. A plain text file normally uses .txt and cannot retain bold, font or layout settings. Executable programs use extensions such as .exe, and compressed archives use .zip or .rar.