ASSEB Class 12 Computer Science & Application 2025 Question Paper Solution [AHSEC HS 2nd Year Computer Science Solved Papers]

[ASSEB Class 12 Computer Science Solved Question Paper 2025, AHSEC Class 12 Computer Science Solved Question Paper 2025, HS 2nd Year Computer Science Solved Question Paper 2025]

2025 – COMPUTER SCIENCE AND APPLICATION (Theory)

Full Marks: 70, Pass Marks: 21, Time: 3 hours

1. Answer any eight (1×8=8)

(a) Who is OOP?
Answer: OOP stands for Object Oriented Programming. It is a way of programming in which data and functions are combined into objects.

(b) What is an instance in OOP?
Answer: An instance is an object created from a class. It is a real example of a class in a program.

(c) What is Data Encapsulation?
Answer: Data Encapsulation means wrapping data and the functions that work on that data into a single unit called a class.

(d) What is Overloading?
Answer: Overloading means using the same function or operator name for different purposes by changing its arguments.

(e) What is Destructor in OOP?
Answer: A destructor is a special function of a class that is automatically called when an object is destroyed to free memory.

(f) What is class member?
Answer: A class member is any variable or function that is defined inside a class.

(g) What is Relational Algebra?
Answer: Relational Algebra is a set of operations used to work with data in relational databases.

(h) What is an Array?
Answer: An array is a collection of elements of the same data type stored under one name.

(i) What is Memory Allocation?
Answer: Memory allocation is the process of giving memory space to variables or objects in a program.

(j) What does FIFO mean?
Answer: FIFO means First In First Out. The element that enters first is removed first.

(k) What is Preprocessor directive?
Answer: A preprocessor directive is a command in C/C++ that starts with # and is processed before compilation (like #include).

(l) What is Relational Database?
Answer: A relational database is a database that stores data in tables with rows and columns.

(m) What is Topology?
Answer: Topology is the physical or logical arrangement of devices in a computer network.

2. Answer any ten (2×10=20)

(a) Define Namespaces.
Answer: A namespace in C++ is a container that holds identifiers like variables, functions, and classes to avoid name conflicts.

(b) Define Sorting.
Answer: Sorting is the process of arranging data in a specific order, such as ascending or descending.

(c) Define POSTFIX notation.
Answer: Postfix notation is a way of writing expressions where the operator comes after the operands (e.g., AB+).

(d) State De-Morgan’s theorems.
Answer:

1. The complement of (A AND B) is (A̅ OR B̅).

2. The complement of (A OR B) is (A̅ AND B̅).

(e) What is the use of Optical Fibre?
Answer: Optical fibre is used to transmit data as light signals over long distances at very high speed.

(f) Describe Satellite Data Communication in Networking.
Answer: Satellite communication uses satellites in space to send and receive data signals between distant locations on Earth.

(g) What can a template in C++ do?
Answer: A template in C++ allows writing generic functions or classes that work with different data types.

(h) Define a Queue.
Answer: A queue is a linear data structure that follows FIFO (First In First Out), where the first element inserted is removed first.

(i) What is OSTREAM?
Answer: OSTREAM is an output stream class in C++ used to send data to output devices like the screen (e.g., cout).

(j) What is Wireless Communication?
Answer: Wireless communication is the transfer of data between devices without using physical cables, using radio or electromagnetic waves.

(k) Describe Bandwidth.
Answer: Bandwidth is the maximum amount of data that can be transmitted over a network in a given time, usually measured in bits per second.

(l) What is K-map simplification?
Answer: K-map simplification is a method used in digital electronics to simplify Boolean expressions using a Karnaugh map.

(m) What is the use of XML?
Answer: XML is used to store and transport data in a structured and platform-independent format.

(n) What is Boolean Algebra?
Answer: Boolean Algebra is a mathematical system used to represent and simplify logical expressions using TRUE and FALSE values.

(o) What is TCP/IP?
Answer: TCP/IP is a set of communication protocols used for connecting devices and transmitting data over the Internet.

3. Answer any nine (3×9=27)

(a) Explain Constructor Overloading.
Answer: Constructor overloading means defining more than one constructor in the same class with different parameters. It allows objects to be created in different ways. For example, one constructor may take no argument and another may take values to initialize data members.

(b) Write the differences between Top-Down and Bottom-Up approaches.
Answer:

1. Top-Down: Program is divided from main problem into smaller sub-problems step by step.

2. Bottom-Up: Small modules are created first and then combined to form the complete program.

3. Top-Down: Focus starts from overall system design.

4. Bottom-Up: Focus starts from detailed components.

(c) Explain the POP and PUSH operations in Stack.
Answer:

1. PUSH: Operation used to insert an element at the top of the stack.

2. POP: Operation used to remove the top element from the stack.
   Stack follows LIFO (Last In First Out), so the last inserted element is removed first.

(d) Describe the Queue and its operations.
Answer: A queue is a linear data structure that follows FIFO (First In First Out).
Main operations:

1. Enqueue: Insert element at the rear.

2. Dequeue: Remove element from the front.

3. Peek/Front: View the front element.

4. IsEmpty: Check if queue has no elements.

(e) Explain Insertion Sorting.
Answer: Insertion sort is a sorting method where elements are taken one by one and placed in their correct position in the sorted part of the list. It works like arranging playing cards in hand by inserting each card in the right place.

(f) Define column constraints in DBMS.
Answer: Column constraints are rules applied to a table column in a database to restrict the type or range of data that can be stored in that column (e.g., NOT NULL, UNIQUE).

(g) Explain Client-side scripting.
Answer: Client-side scripting means running scripts on the user’s browser instead of the server. It is used to make web pages interactive (e.g., JavaScript).

(h) Write about Logic Gates.
Answer: Logic gates are basic digital electronic circuits that perform logical operations on binary inputs (0 or 1) to produce an output. Examples: AND, OR, NOT, NAND, NOR, XOR.

(i) Explain HTML.
Answer: HTML (HyperText Markup Language) is a markup language used to create and structure web pages using tags like headings, paragraphs, images, and links.

(j) Define DDL and DML.
Answer:

1. DDL (Data Definition Language): Commands used to define or change database structure (e.g., CREATE, ALTER, DROP).

2. DML (Data Manipulation Language): Commands used to insert, update, delete, and retrieve data (e.g., INSERT, UPDATE, DELETE, SELECT).

(k) Mention the uses of Co-axial cable.
Answer: Co-axial cable is used to transmit data, television signals, and internet signals with less interference. It is commonly used in cable TV and broadband connections.

(l) Differentiate one- and two-dimensional arrays.
Answer:

1. One-dimensional array: Stores elements in a single list using one index (e.g., marks[5]).

2. Two-dimensional array: Stores elements in rows and columns using two indices (e.g., marks[3][4]).

3. One-dimensional: Represents a linear collection.

4. Two-dimensional: Represents a table or matrix.

(m) Write about Switching Techniques.
Answer: Switching techniques are methods used in networks to send data from source to destination.
Main types:

1. Circuit Switching: Dedicated path is established before communication (e.g., telephone).

2. Packet Switching: Data is divided into packets and sent separately (e.g., Internet).

3. Message Switching: Entire message is sent and stored at each node before forwarding.

4. Answer any three (5×3=15)

(a) Explain different clauses used in SQL.
Answer: SQL clauses are components of SQL statements that specify conditions, grouping, and ordering of data in database queries. They control how data is retrieved and displayed from tables.

The main SQL clauses are the following:

1. SELECT clause:
   It specifies the columns or fields to be retrieved from a table.
   Example: SELECT name, marks FROM student;

2. FROM clause:
   It specifies the table from which data is taken.
   Example: FROM student;

3. WHERE clause:
   It is used to filter records based on a condition. Only rows that satisfy the condition are returned.
   Example: WHERE marks > 50;

4. GROUP BY clause:
   It groups rows having the same values in specified columns into summary rows. It is used with aggregate functions like SUM, COUNT, AVG.
   Example: GROUP BY class;

5. HAVING clause:
   It is used to apply conditions on grouped data (after GROUP BY).
   Example: HAVING COUNT(*) > 5;

6. ORDER BY clause:
   It sorts the result in ascending (ASC) or descending (DESC) order.
   Example: ORDER BY marks DESC;

Thus, SQL clauses help in selecting, filtering, grouping, and arranging data properly in database queries.

(b) Explain about Domain Names.
Answer: A domain name is the unique and human-readable name of a website used to identify it on the Internet. It is used instead of remembering numerical IP addresses.

Every website has an IP address (like 142.250.183.14), but domain names make it easy for users to access websites, such as www.google.com.

Structure of a domain name:  A domain name has different parts separated by dots:

1. Top-Level Domain (TLD):
   The last part of the domain.
   Examples: .com, .org, .edu, .in

2. Second-Level Domain:
   The main name chosen by the organization or user.
   Example: google in google.com

3. Subdomain (optional):
   A prefix added before domain.
   Example: www in www.google.com

Working of Domain Name:
When a user enters a domain name in a browser, the Domain Name System (DNS) converts it into the corresponding IP address of the server. Then the browser connects to that server and loads the website.

Importance of Domain Names:

1. Easy to remember

2. Unique identity for websites

3. Used for branding and online presence

4. Helps access Internet services easily

Thus, domain names act as the readable addresses of websites on the Internet.

(c) Explain Boolean operators.
Answer:  Boolean operators are logical operators used to combine or modify conditions in programming and Boolean algebra. They work with TRUE (1) and FALSE (0) values and produce a logical result.

The main Boolean operators are the following:

1. AND (&&):  It gives TRUE only when both conditions are TRUE.
   Example: If A=1 and B=1 → A AND B = 1

2. OR (||):  It gives TRUE if at least one condition is TRUE.
   Example: If A=1 and B=0 → A OR B = 1

3. NOT (!):  It reverses the logical value (TRUE becomes FALSE and FALSE becomes TRUE).
   Example: If A=1 → NOT A = 0
   
   

Use in programming:  Boolean operators are used in decision-making statements like if, while, and conditions.

Example in C++:
if (marks > 40 && attendance > 75)
Here AND ensures both conditions are satisfied.

Thus, Boolean operators help in forming logical expressions and controlling program flow.

(d) Write a C++ program to sort numbers entered by the user.
Answer:

#include<iostream> using namespace std; int main() {     int n, i, j, temp;          cout<<"Enter number of elements: ";     cin>>n;          int a[100];          cout<<"Enter numbers:\n";     for(i=0;i<n;i++)         cin>>a[i];          // Bubble sort     for(i=0;i<n-1;i++)     {         for(j=0;j<n-i-1;j++)         {             if(a[j] > a[j+1])             {                 temp = a[j];                 a[j] = a[j+1];                 a[j+1] = temp;             }         }     }          cout<<"Sorted numbers:\n";     for(i=0;i<n;i++)         cout<<a[i]<<" ";          return 0; }

(e) Explain the difference between Traversal and Searching.

(f) What are the differences between SMTP and POP3 protocols?

(e) Explain the difference between Traversal and Searching.
Answer:

Basis	Traversal	Searching
Meaning	Visiting each element of a data structure one by one	Finding a specific element in a data structure
Purpose	To process or display all elements	To locate a particular element
Elements visited	All elements are visited	Only until the element is found
Result	Performs operation on every item	Gives position or existence of item
Example	Printing all array elements	Finding value 25 in array

(f) What are the differences between SMTP and POP3 protocols?
Answer:

Basis	SMTP	POP3
Full form	Simple Mail Transfer Protocol	Post Office Protocol version 3
Function	Used to send emails	Used to receive emails
Mail type	Outgoing mail	Incoming mail
Operation type	Push protocol	Pull protocol
Direction	Client → Mail server	Mail server → Client
Purpose	Transfers email to server or between servers	Downloads email from server to user device
Port (common)	25 or 587	110

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