12th Computer Applications Important 1 Mark Questions Chapter Wise

By Ravi Kumar · 15 Sep 2026 · 4 min read

The one-mark section of Class 12 Computer Applications rewards precise memory. Almost every question asks for a single fact: an expansion, a shortcut key, a function name, a year or a standard. Below is a chapter-by-chapter map of the facts the book back questions are built on.

Unit 1: Multimedia

The five components of multimedia: text, images, sound, video and animation
Raster images are made of pixels; vector images are made of geometric shapes
JPEG (Joint Photographic Experts Group) is a raster format; EPS is a vector format
RTF was introduced by Microsoft; AIFF was developed by Apple

Unit 2: An Introduction to Adobe PageMaker

DTP stands for Desktop Publishing
The area outside the page border is the pasteboard
Shortcuts: Ctrl + W closes a document, Ctrl + P prints, Ctrl + A selects all
New and Place are both in the File menu

Unit 3: Introduction to Database Management System

An ER diagram shows the logical structure of a database
An entity set without enough attributes for a primary key is a weak entity set
A tuple is a row; a schema is the organisational view of the whole database
MySQL is a free, open source relational DBMS

Unit 4: PHP: Hypertext Preprocessor

PHP files use the .php extension and PHP supports eight data types
Every variable begins with $, and variable names are case-sensitive
=== is the identical operator; float holds decimal numbers

Unit 5: Functions and Arrays in PHP

Pre-defined functions are called built-in functions; user-defined ones start with function
PHP has three types of arrays: indexed, associative and multidimensional
Indexing starts at 0, so the third element has index 2

Units 6 and 7: Conditional Statements and Loops in PHP

while is a loop, not a conditional statement
In a switch, case labels each path, default runs when nothing matches, and break ends the switch
for and while are entry-check loops; do...while is exit-check
The initialization part of a for loop runs only once; foreach iterates over arrays

Unit 8: Forms and Files

Checkboxes allow multiple selections; radio buttons allow only one
There are two types of validation: client-side and server-side
fopen() opens, fread() reads and fclose() closes a file

Unit 9: Connecting PHP and MySQL

mysqli_connect() takes four parameters, mysqli_query() takes two and mysqli_close() takes one
MySQLi functions are supported from PHP version 5
mysqli_num_rows() returns the number of rows; mysqli_select_data() does not exist

Units 10 and 11: Computer Networks, Examples and Protocols

Wi-Fi stands for Wireless Fidelity; mobile network coverage is divided into cells
Heated personal attacks in a forum are called a flame war
Intranet is restricted to an organisation; extranet shares with suppliers and partners
SMTP provides e-mail, DNS maps names to numbers, HTTPS secures transmission
The transport layer of the OSI model handles error checking and successful delivery

Unit 12: Domain Name System (DNS)

IPv6 addresses use 128 bits; a node label can have at most 63 characters
There are two types of URL, absolute and relative
The resolver starts the mapping of a name to an IP address; root name servers are maintained by ICANN

Unit 13: Network Cabling

Tim Berners-Lee invented the World Wide Web
Coaxial cable is used in cable TV; optical fibre transmits data as light
RJ45 (8 pins) is the Ethernet connector; RJ21 is the champ connector
Cross over wiring connects two computers directly

Unit 14: Open Source Concepts

NS2 is a network simulator built with C++ and OTcl
Trace files record every event in a simulation
OpenNMS is open source network monitoring software, released in 1999

Units 15 and 16: E-Commerce and Electronic Payment Systems

SME stands for small and medium-sized enterprises; off-shoring means outsourcing to another country
The first wave of e-commerce ran from 1995 to 2003, not 1985 to 1990
Payment systems are classified as micro and macro by monetary value
A debit card means pay now; ECS stands for Electronic Clearing Services; a VPA is a unique ID
On a card number, the first digit is the MII code, the first six digits are the BIN and the last digit is the check digit

Units 17 and 18: E-Commerce Security Systems and EDI

Using a stolen card to buy online is clean fraud
Asymmetric encryption uses different keys; PGP stands for Pretty Good Privacy
SET secures card transactions over the Internet and was developed in 1996
EDIFACT is the international EDI standard; TDCC was the first industry-specific one
Ed Guilbert is called the father of EDI

How to revise this section

Turn each list above into questions and test yourself against a timer rather than re-reading. Anything you miss goes onto a single page. The full solved sets, with an explanation for every option, are on the Class 12 Computer Applications section, and each chapter has a practice test where you choose the number of questions.