I85PREP
⌘ K
Sri Lanka ICT Service Exam study materials
Sri Lanka ICT Service Exam study resources

Sri Lanka ICT Service Exam practice questions

One question at a time. Build your Sri Lanka ICT Service Exam understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Information and Communication Technology Fundamentals

In a computer system, which component is responsible for performing arithmetic and logical operations?

  1. Arithmetic Logic Unit Correct answer.
  2. Input device
  3. Main memory
  4. Control Unit

Explanation

The Arithmetic Logic Unit (ALU) inside the CPU executes arithmetic operations such as addition and logical operations such as AND, OR and comparison. The control unit only directs and coordinates, while memory and input devices store or supply data.

Question 2Information and Communication Technology Fundamentals

Which storage type loses its stored contents when the computer is switched off?

  1. Hard disk drive
  2. Read-only memory
  3. Volatile RAM Correct answer.
  4. Solid state drive

Explanation

Volatile memory such as RAM requires continuous power to retain data, so its contents are lost at power-off. Hard disks, SSDs and ROM are non-volatile and keep data without power.

Question 3Information and Communication Technology Fundamentals

In the OSI reference model, which layer is responsible for routing packets between different networks?

  1. Network layer Correct answer.
  2. Transport layer
  3. Data link layer
  4. Session layer

Explanation

The network layer handles logical addressing and routing, deciding the path packets take across interconnected networks. The data link layer deals with local frame delivery, transport handles end-to-end connections, and session manages dialogue control.

Question 4Information and Communication Technology Fundamentals

Which of the following is an example of system software?

  1. Operating system Correct answer.
  2. Web browser
  3. Word processing application
  4. Spreadsheet package

Explanation

System software manages hardware and provides a platform for applications; the operating system is the primary example. Word processors, spreadsheets and browsers are application software written to perform user tasks.

Question 5Information and Communication Technology Fundamentals

What is the decimal value of the binary number 1011?

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

Explanation

Reading place values from the left, 1011 equals 8 + 0 + 2 + 1, which totals 11. Each position doubles in value from right to left in base two.

Question 6Information and Communication Technology Fundamentals

Which protocol is used to transfer web pages securely over the internet?

  1. FTP
  2. SNMP
  3. SMTP
  4. HTTPS Correct answer.

Explanation

HTTPS is HTTP carried over TLS, encrypting web traffic between browser and server. FTP transfers files without this web encryption, SMTP sends mail, and SNMP manages network devices.

Question 7Information and Communication Technology Fundamentals

In a database, what does a primary key do?

  1. Links two tables permanently
  2. Sorts records automatically
  3. Encrypts every record in the table
  4. Uniquely identifies each record in a table Correct answer.

Explanation

A primary key is a column or set of columns whose value is unique and non-null for every row, so each record can be identified. It does not encrypt data, and relationships to other tables are made with foreign keys.

Question 8Information and Communication Technology Fundamentals

Which of the following is the best example of a strong password practice?

  1. Using the same password on every site
  2. Using your date of birth
  3. Using a long passphrase with mixed characters Correct answer.
  4. Using your username as the password

Explanation

Long passphrases combining upper and lower case letters, digits and symbols are harder to guess or crack. Personal details and reused credentials are easily discovered and allow one breach to compromise many accounts.

Question 9Information and Communication Technology Fundamentals

A small office wants to connect five computers so they can share files and a printer without internet access. Which device is most appropriate?

  1. A plotter
  2. A switch Correct answer.
  3. A modem
  4. A scanner

Explanation

A switch connects devices within a local area network and forwards frames between them, allowing file and printer sharing. A modem connects to an external line, while scanners and plotters are peripherals, not network devices.

Question 10Information and Communication Technology Fundamentals

What is the main purpose of cache memory in a computer?

  1. To store the operating system permanently
  2. To reduce the average time the CPU takes to access data Correct answer.
  3. To back up user files automatically
  4. To convert analog signals to digital form

Explanation

Cache is small, fast memory close to the CPU that holds frequently used instructions and data, reducing average access time compared with fetching from main memory. It is volatile and not used for permanent storage or backups.

Question 11Information and Communication Technology Fundamentals

A technician assigns the address 192.168.10.25 with subnet mask 255.255.255.0 to a workstation. Which statement about this address is correct?

  1. It is a public address routable on the internet
  2. It is a private address within the 192.168.0.0 range Correct answer.
  3. It is a loopback address
  4. It is a broadcast address

Explanation

Addresses beginning 192.168 are reserved for private networks under RFC 1918 and are not routed on the public internet without translation. The loopback address is 127.0.0.1, and the broadcast address for this subnet would end in 255.

Question 12Information and Communication Technology Fundamentals

Which topology connects every device to a single central device, so that failure of that central device stops all communication?

  1. Star topology Correct answer.
  2. Ring topology
  3. Bus topology
  4. Mesh topology

Explanation

In a star topology each node links to a central hub or switch, so a central failure disables the whole network while a single cable failure affects only one node. A bus shares one backbone, a ring passes data node to node, and a mesh offers multiple paths.

Question 13Information and Communication Technology Fundamentals

In a spreadsheet, a formula in cell C1 reads =A1*B1. If this formula is copied to C2, what will it become?

  1. =A1*B1
  2. =A1*B2
  3. =A2*B2 Correct answer.
  4. =A3*B3

Explanation

By default spreadsheet references are relative, so copying one row down shifts every row reference by one while keeping the column letters. Thus A1 and B1 both become A2 and B2.

Question 14Information and Communication Technology Fundamentals

Which file extension typically indicates a compressed archive that may contain several files?

  1. .html
  2. .zip Correct answer.
  3. .csv
  4. .txt

Explanation

A .zip file is an archive produced by compression software and can hold one or many files in reduced size. Text, HTML and CSV files are plain data formats without archive or compression structure.

Question 15Information and Communication Technology Fundamentals

What is the primary function of the Domain Name System (DNS)?

  1. To filter malicious web content
  2. To encrypt email messages
  3. To assign dynamic IP addresses to hosts
  4. To translate domain names into IP addresses Correct answer.

Explanation

DNS resolves human-readable domain names such as example.lk into the numeric IP addresses used for routing. Dynamic address assignment is done by DHCP, encryption by protocols such as TLS, and content filtering by dedicated security systems.

Question 16Information and Communication Technology Fundamentals

In a relational database, a foreign key is used mainly to do which of the following?

  1. Guarantee that a column contains no duplicates
  2. Enforce a link to a primary key in another table Correct answer.
  3. Store large binary objects
  4. Speed up sorting of query results

Explanation

A foreign key holds values that must match a primary key in a related table, enforcing referential integrity between the two tables. Uniqueness is enforced by unique or primary keys, while sorting and large object storage are separate concerns.

Question 17Information and Communication Technology Fundamentals

A user reports that a computer powers on but shows no display and beeps repeatedly at startup. Which step should be taken first in a systematic troubleshooting process?

  1. Check the monitor cable and memory modules Correct answer.
  2. Reinstall the operating system
  3. Format the drive and restore data
  4. Replace the hard disk

Explanation

Startup beeps indicate a hardware self-test failure, commonly caused by loose or faulty memory or display connections. Checking cables and reseating memory follows the principle of testing the simplest and most likely causes before destructive actions.

Question 18Information and Communication Technology Fundamentals

Which of the following best describes the role of a firewall in a network?

  1. It controls traffic between networks according to defined rules Correct answer.
  2. It converts digital signals into analog signals
  3. It assigns domain names to web servers
  4. It stores backup copies of server data

Explanation

A firewall inspects packets crossing a boundary and permits or blocks them according to configured rules, providing access control. Signal conversion is done by modems, backups by storage systems, and name assignment by DNS administration.

Question 19Information and Communication Technology Fundamentals

A company wants to prevent employees from accessing social media sites during working hours. Which solution most directly achieves this?

  1. Adding more RAM to the office computers
  2. Installing antivirus software on each PC
  3. Configuring a content filter on the network gateway Correct answer.
  4. Increasing the bandwidth of the internet link

Explanation

A content filter at the network gateway inspects requests and blocks categories or specific domains such as social media. Antivirus addresses malware, extra bandwidth and RAM affect performance only and do not restrict access.

Question 20Information and Communication Technology Fundamentals

What is the main advantage of using cloud storage for an organisation's files?

  1. Files can be accessed from multiple locations over the internet Correct answer.
  2. Files are guaranteed to be immune to all security threats
  3. Files no longer need any access control
  4. Files are always faster to open than local files

Explanation

Cloud storage keeps files on remote servers, so authorised users can reach them from any location with internet access. It still requires access control and security measures, and speed depends on network conditions.

Question 21Information and Communication Technology Fundamentals

An organisation wants to reduce the risk of losing data if a hard disk fails. Which measure addresses this most directly?

  1. Defragmenting the disk weekly
  2. Keeping regular backups on separate media Correct answer.
  3. Increasing the size of the page file
  4. Running a disk cleanup utility

Explanation

Backups on separate media allow data to be restored if the primary disk fails, directly reducing loss risk. Defragmentation, page file size and disk cleanup affect performance or space, not recoverability.

Question 22Information and Communication Technology Fundamentals

A TCP connection uses a three-way handshake. What is the correct sequence of messages exchanged to establish the connection?

  1. SYN, SYN-ACK, ACK Correct answer.
  2. FIN, ACK, SYN
  3. ACK, SYN, FIN
  4. SYN, ACK, SYN-ACK

Explanation

The client sends SYN to request a connection, the server replies with SYN-ACK acknowledging it and synchronising in reverse, and the client sends ACK to complete establishment. FIN messages belong to connection termination, not setup.

Question 23Information and Communication Technology Fundamentals

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

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

Explanation

The mask 255.255.255.192 leaves six host bits, giving 2^6 = 64 addresses per subnet. Subtracting the network and broadcast addresses leaves 62 usable host addresses.

Question 24Information and Communication Technology Fundamentals

A programmer writes a loop that never modifies its controlling variable, so the condition never becomes false. What type of error is this?

  1. Compilation warning
  2. Syntax error
  3. Runtime error
  4. Logical error causing an infinite loop Correct answer.

Explanation

The code is syntactically valid and may run, but the logic is flawed because the loop condition can never be satisfied, producing an infinite loop. Syntax errors prevent compilation, and runtime errors such as division by zero stop execution abnormally.

Question 25Information and Communication Technology Fundamentals

In symmetric key cryptography, two parties wish to communicate securely. What is the main practical challenge compared with public key cryptography?

  1. Symmetric algorithms cannot encrypt large files
  2. Encryption is far slower than with public keys
  3. The shared secret key must be distributed securely in advance Correct answer.
  4. Symmetric keys cannot be changed once generated

Explanation

Symmetric encryption uses one shared key, so both parties must obtain it through a secure channel before communicating, which is the key distribution problem. It is generally faster than public key methods and can encrypt large data and be rotated.

Question 26Information and Communication Technology Fundamentals

Which type of software is an operating system such as Linux or Windows classified as?

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

Explanation

An operating system is system software because it manages hardware resources and provides the platform on which other programs run. Application software performs user-oriented tasks, utility software maintains the system, and firmware is stored in hardware.

Question 27Information and Communication Technology Fundamentals

A student wants to send an email attachment that must open on the recipient's computer exactly as designed, preserving layout and fonts. Which file format is most suitable?

  1. TXT
  2. PDF Correct answer.
  3. CSV
  4. HTML

Explanation

PDF preserves the visual layout, fonts and formatting of a document across different systems, which is why it is standard for fixed-format sharing. TXT and CSV store only plain data without layout, and HTML rendering varies between browsers.

Question 28Information and Communication Technology Fundamentals

An employee receives an email claiming to be from the bank and asking them to confirm their password through a link. Which security threat does this describe?

  1. Denial of service attack
  2. Phishing Correct answer.
  3. SQL injection
  4. Brute force attack

Explanation

Phishing is a social-engineering attack that impersonates a trusted organisation to trick users into revealing credentials or clicking malicious links. Denial of service, SQL injection and brute force target systems or logins technically rather than deceiving the user.

Question 29Information and Communication Technology Fundamentals

A spreadsheet cell contains the formula =SUM(A1:A5). A user inserts a new row between rows 3 and 4, entering a positive numeric value in column A. What happens to the total?

  1. The total increases because the range expands to include the new row Correct answer.
  2. The formula returns an error until it is re-entered
  3. The total decreases because the new row replaces an existing value
  4. The total stays the same because the range is fixed

Explanation

When rows are inserted inside a referenced range, spreadsheets automatically adjust the range so the new row is included, and the sum rises by the inserted value. The formula is not broken and no existing value is replaced.

Question 30Information and Communication Technology Fundamentals

A company stores customer records in a table where the same customer address is repeated for every order. Which normalisation step most directly removes this redundancy?

  1. Splitting the address into a separate customer table referenced by a key Correct answer.
  2. Sorting the table by customer name
  3. Encrypting the address column
  4. Adding an index to the order table

Explanation

Moving the repeated address into its own table and linking it through a key removes the duplication, which is the essence of normalisation. Indexing, encryption and sorting change performance or security but leave the redundant data in place.

Question 31Computer Hardware, Operating Systems and Networking

A user reports that a desktop computer powers on but produces no display output, and the monitor shows 'No Signal'. Which component should be checked first to confirm basic video output before investigating other causes?

  1. The operating system's display resolution setting
  2. The graphics card or onboard video connector and the cable seated between it and the monitor Correct answer.
  3. The RAM modules' speed rating against the motherboard specification
  4. The hard disk drive's SATA data cable and power connector

Explanation

A 'No Signal' message means the monitor is not receiving a video signal, so the physical path from the video output to the monitor must be verified first. Reseating the video cable and confirming the correct output port (dedicated card versus onboard) is the standard first diagnostic step. Storage, RAM speed, and OS resolution cannot produce a signal at all if the link is broken.

Question 32Computer Hardware, Operating Systems and Networking

Which type of memory is directly accessible by the CPU and loses its contents when power is removed?

  1. Magnetic disk
  2. Volatile RAM Correct answer.
  3. ROM
  4. Flash storage

Explanation

RAM is volatile memory that the CPU reads and writes directly during program execution, and its contents are lost at power-off. ROM and flash retain data without power, and magnetic disks are non-volatile secondary storage. Only volatile RAM fits both conditions in the stem.

Question 33Computer Hardware, Operating Systems and Networking

In the TCP/IP model, which layer is responsible for logical addressing and routing of packets between networks?

  1. Transport layer
  2. Network access layer
  3. Internet layer Correct answer.
  4. Application layer

Explanation

The internet layer of the TCP/IP model handles logical addressing (IP addresses) and routing of packets across interconnected networks. The transport layer handles end-to-end delivery and ports, while the application layer hosts protocols such as HTTP. The network access layer deals with the local link.

Question 34Computer Hardware, Operating Systems and Networking

Which file system is the native default for modern Windows installations and supports features such as journaling and file-level permissions?

  1. NTFS Correct answer.
  2. ISO 9660
  3. FAT32
  4. ext4

Explanation

NTFS is the default file system for current Windows versions and provides journaling, access control lists, and large volume support. FAT32 lacks journaling and permissions, ext4 is a Linux file system, and ISO 9660 is used for optical media.

Question 35Computer Hardware, Operating Systems and Networking

What is the primary function of the BIOS or UEFI firmware during system startup?

  1. It manages user account passwords for network logon
  2. It performs hardware initialisation and locates a bootable device to start the operating system Correct answer.
  3. It compiles application source code before the operating system loads
  4. It provides the graphical desktop environment for the user

Explanation

Firmware performs power-on self-test and hardware initialisation, then locates and hands control to a bootloader on a bootable device. It does not compile applications, manage network accounts, or provide the desktop, which are operating system responsibilities.

Question 36Computer Hardware, Operating Systems and Networking

Which device operates at the data link layer of the OSI model and forwards frames based on MAC addresses?

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

Explanation

A switch builds a MAC address table and forwards frames only to the port where the destination MAC address is known, which is data link layer behaviour. A hub and a repeater simply regenerate signals at the physical layer, while a router forwards packets using IP addresses at the network layer.

Question 37Computer Hardware, Operating Systems and Networking

Which interface is the current standard for connecting internal hard disk drives and solid state drives in desktop computers?

  1. SATA Correct answer.
  2. VGA
  3. PS/2
  4. Parallel port

Explanation

SATA is the widely used interface for internal HDDs and SSDs, providing a serial data connection and a separate power connector. PS/2 is for legacy keyboards and mice, VGA is an analogue video interface, and parallel ports are obsolete for storage.

Question 38Computer Hardware, Operating Systems and Networking

A technician needs to assign a fixed IPv4 address to a server so that clients always reach it at the same address. Which configuration method should be used?

  1. Rely on the default gateway to assign the address
  2. Obtain the address automatically through DHCP
  3. Configure a static IP address on the server Correct answer.
  4. Configure the server to use APIPA

Explanation

A static IP address is manually assigned so it does not change between reboots, which is required for servers that clients must reach reliably. DHCP leases can change, APIPA addresses are self-assigned and not routable, and a default gateway forwards traffic rather than assigning addresses.

Question 39Computer Hardware, Operating Systems and Networking

Which component converts alternating current from the wall outlet into the regulated direct current voltages required by a desktop computer's internal parts?

  1. The motherboard chipset
  2. The voltage regulator module on the CPU
  3. The power supply unit Correct answer.
  4. The uninterruptible power supply

Explanation

The power supply unit performs AC-to-DC conversion and delivers regulated DC rails such as +12 V, +5 V, and +3.3 V to the system. A UPS provides battery backup but still outputs AC, and the chipset and CPU voltage regulator work with DC already supplied by the PSU.

Question 40Computer Hardware, Operating Systems and Networking

A user's laptop connects to the office Wi-Fi but cannot reach internet sites, while other devices on the same network can. Which setting should be verified first on the laptop?

  1. The hard disk's free space
  2. The laptop's screen brightness level
  3. The IPv4 default gateway and DNS server addresses assigned to the wireless adapter Correct answer.
  4. The laptop's keyboard layout

Explanation

Successful association with the Wi-Fi network but failure to reach internet sites typically points to incorrect gateway or DNS settings on that adapter. Verifying the gateway and DNS values confirms whether the laptop can route off the local network and resolve names. Brightness, disk space, and keyboard layout cannot affect IP routing.

Question 41Computer Hardware, Operating Systems and Networking

Which statement correctly distinguishes a process from a thread in a modern operating system?

  1. A process has its own address space and resources, while threads within a process share that address space Correct answer.
  2. A process shares its address space with all other processes, while a thread has a private address space
  3. A thread can contain multiple processes, each with separate memory
  4. A process and a thread are identical in resource allocation but differ only in name

Explanation

A process is an executing program instance with its own virtual address space and resources. Threads are execution units inside a process that share the process's memory and open resources, which makes communication faster but requires synchronisation.

Question 42Computer Hardware, Operating Systems and Networking

A subnet mask of 255.255.255.192 is applied to a network. How many usable host addresses does each subnet provide?

  1. 254
  2. 126
  3. 62 Correct answer.
  4. 30

Explanation

The mask 255.255.255.192 leaves six host bits (64 minus the network and broadcast addresses), giving 62 usable hosts. Each additional borrowed bit halves the host count, so 30, 126, and 254 correspond to different masks.

Question 43Computer Hardware, Operating Systems and Networking

Which RAID level provides disk mirroring so that data remains available if one drive fails, while using exactly two drives?

  1. RAID 1 Correct answer.
  2. RAID 0
  3. RAID 5
  4. RAID 6

Explanation

RAID 1 mirrors identical data across two drives, so a single drive failure does not lose data. RAID 0 stripes without redundancy, and RAID 5 and RAID 6 require at least three and four drives respectively and use parity.

Question 44Computer Hardware, Operating Systems and Networking

Which command-line utility is used on Windows to display the current IP configuration, including address, subnet mask, and default gateway?

  1. tracert
  2. netstat
  3. ipconfig Correct answer.
  4. ping

Explanation

ipconfig reports the adapter's IP address, subnet mask, and default gateway, and with the /all switch shows additional details such as MAC address and DNS servers. ping tests reachability, tracert traces the route, and netstat lists connections.

Question 45Computer Hardware, Operating Systems and Networking

What is the main purpose of virtual memory in an operating system?

  1. To encrypt data stored on the hard disk
  2. To extend usable memory by paging inactive data to secondary storage Correct answer.
  3. To increase the physical clock speed of the processor
  4. To provide a backup copy of the operating system for recovery

Explanation

Virtual memory lets the operating system move less-used pages from RAM to a swap file or partition on disk, extending the effective memory available to programs. It does not change processor clock speed, serve as an OS backup, or provide encryption.

Question 46Computer Hardware, Operating Systems and Networking

Which cable type is required to connect a computer's network adapter to a switch port for normal operation?

  1. A crossover cable in all cases
  2. A rollover console cable
  3. A straight-through cable Correct answer.
  4. A null modem serial cable

Explanation

A straight-through cable connects a computer (an end device) to a switch, because the transmit pins at one end map to the receive pins at the other. Crossover cables were used between like devices, while rollover and null modem cables are for console or serial connections.

Question 47Computer Hardware, Operating Systems and Networking

Which Windows tool is used to view and manage disk partitions, including creating, formatting, and extending volumes?

  1. Task Scheduler
  2. Disk Management Correct answer.
  3. Event Viewer
  4. Device Manager

Explanation

Disk Management displays physical disks and volumes and allows creating, formatting, extending, shrinking, and assigning drive letters. Device Manager manages hardware drivers, Task Scheduler automates tasks, and Event Viewer reviews logs.

Question 48Computer Hardware, Operating Systems and Networking

A workstation is configured with the address 169.254.10.25 and a subnet mask of 255.255.0.0. What does this address indicate?

  1. The workstation received a valid lease from a DHCP server
  2. The workstation could not contact a DHCP server and self-assigned a link-local address Correct answer.
  3. The workstation has a static address assigned by the administrator
  4. The workstation is using a public internet address

Explanation

The 169.254.0.0/16 range is the APIPA link-local range that Windows assigns when no DHCP server responds. Such an address allows communication only on the local segment and signals a DHCP or connectivity problem.

Question 49Computer Hardware, Operating Systems and Networking

Which of the following best describes the role of DNS in a network?

  1. It resolves host names to IP addresses Correct answer.
  2. It forwards packets between different subnets
  3. It assigns IP addresses to hosts automatically
  4. It encrypts traffic between web browsers and servers

Explanation

DNS translates human-readable names such as a website address into IP addresses so clients can reach the correct server. Address assignment is done by DHCP, encryption by protocols such as TLS, and packet forwarding by routers.

Question 50Computer Hardware, Operating Systems and Networking

Which CPU feature allows a single physical core to execute two instruction streams concurrently by maintaining two sets of architectural registers?

  1. Cache coherency
  2. Superscalar pipelining
  3. Hyper-Threading or simultaneous multithreading Correct answer.
  4. Overclocking

Explanation

Simultaneous multithreading, marketed by Intel as Hyper-Threading, exposes two logical processors per physical core so that two threads can share execution units. Superscalar pipelining issues multiple instructions per cycle within one stream, overclocking raises clock frequency, and cache coherency keeps caches consistent.