[SOLUTION] HERALD Pre-Board Examination - 2081 (2025)
HERALD Pre-Board Examination - 2081
Grade: XII (Science)
Subject: Computer Science (4281)
Group 'A'
Multiple Choice Questions
[9×1=9]
- Which
SQL keyword is used to retrieve data from a table?
a) SELECT
b) WHERE
c) FROM
d) JOIN
Note: The SELECT keyword is used to query data from a
table in SQL.
- Which
of the following techniques is used to grant privileges to users in a
database?
a) Authentication
b) Authorization
c) Isolation
d) Backup
Note: Authorization is the process of granting specific
privileges or permissions to users in a database, allowing them access to
certain resources.
- Which
JavaScript function is used for input?
a) alert()
b) prompt()
c) confirm()
d) console.log()
Note: The prompt() function in JavaScript is used to take
input from the user through a dialog box.
- What
is the type of inheritance shown in the following figure?
a) Single inheritance
b) Multilevel inheritance
c) Hierarchical inheritance
d) Multiple inheritance
Note: Multilevel inheritance occurs when a class inherits
from another class, and that class is derived from another class, forming a
hierarchy.
- System
Requirement Specification (SRS) document is used in which stage of
software development?
a) Planning
b) Analysis
c) Development
d) Testing
Note: The System Requirement Specification (SRS) document
is produced in the analysis phase of software development, detailing the
functional and non-functional requirements.
- What
is not a service of cloud computing?
a) SaaS
b) PaaS
c) IaaS
d) NaaS
Note: NaaS (Network as a Service) is not considered a
standard service in cloud computing, while SaaS, PaaS, and IaaS are widely
recognized models.
- Data
is represented in bits in which layer of the OSI model?
a) Physical
b) Data link
c) Network
d) Presentation
Note: Data is represented in bits at the physical layer
of the OSI model, which is responsible for transmitting raw data over physical
connections.
- Which
of the functions is used to read a character from a file?
a) getc()
b) getch()
c) getchar()
d) putc()
Note: The getc() function is used in C to read a single character
from a file.
- How
many modes of communication are there?
a) 1
b) 2
c) 3
d) 4
Note: There are three modes of communication:
unidirectional(simplex), bidirectional(half-duplex), and
multidirectional(full-duplex). These modes describe how data is transmitted
between parties.
Group 'B'
Short answer questions: [5
x 5 = 25]
10. Explain
about 2NF and 3NF with example.
OR
What are DDL and DML statements? Write with
example queries.
- What
is event handling? How do you add an event handler in JavaScript? Give an
example.
Ans:
In JavaScript, an event
handler is a function that gets executed when a specific event occurs,
such as a mouse click, a key press, or a form submission. We can add event
handlers using either of the following methods:
a) Using the onclick attribute
(Inline event handling)
b) Using addEventListener()
(External event handling)
A simple example of an event
handler using the onclick attribute in JavaScript is as follows:
<!DOCTYPE html>
<html>
<head>
<title>Hello World</title>
</head>
<body>
<button
onclick="showMessage()">Click me</button>
<script>
function showMessage()
{
document.write("Hello, World!");
}
</script>
</body>
</html>
Explanation:
The showMessage() function
uses document.write() to directly write the text "Hello,
World!" to the page.
(Click me) button triggers the
showMessage() function when clicked
OR
Define the syntax of database
connectivity in PHP. Write a server-side scripting code to insert data into the
table 'student' having fields (first name, last name and marks). Assume that
server name="localhost", username="root", password="",
database name="student".
Ans:
Syntax for Database Connectivity:
$con = new mysqli($servername,
$username, $password, $database);
OR
$con = mysqli_connect($servername,
$username, $password, $database);
A server-side scripting code to
insert data into the table student having fields (first name, last name and
marks) is as follows:
<?php
// Step 1: Database configuration
$servername =
"localhost";
$username = "root";
$password = "";
$database = "student";
//Step2: Database connection
$con = new mysqli($servername,
$username, $password, $database);
// Step 3: Check connection
if ($con->connect_error)
{
die("Connection failed: " . $con->connect_error);
} else {
echo
"Connected successfully!";
}
// Step 4: Prepare the SQL
statement for insertion
$sql = "INSERT INTO student
(first_name, last_name, mark)
VALUES ('Madhav', 'Sapkota', 30)";
// Step 5: Execute the query and
check if data is inserted
if ($con->query($sql) === TRUE)
{
echo "Data
inserted successfully";
} else {
echo
"Error: " . $sql . "<br>" . $con->error;
}
// Step 6: Close connection
$con->close();
?>
- Explain
about the big data with its features.
Ans:
Big Data is a term that describes
extremely large and complex datasets that traditional data processing methods
can't handle efficiently. It covers data that is characterized by high volume,
high velocity, and high variety, often requiring advanced techniques and
technologies to analyze and extract meaningful information. Some examples
of Big Data are as follows:
a) Social media data (Facebook,
Twitter, Instagram)
b) E-commerce transactions (Amazon,
Flipkart)
c) Healthcare records (EHRs, MRI
scans)
d) Banking and financial
transactions
e) IoT sensor data (smart cities,
wearables)
f) Search engine data (Google, Bing),
etc.
Features of big data are as
follows:
a) Volume: Enormous amounts of
data are generated every day from various sources.
b) Velocity: Data is generated
and processed rapidly, requiring real-time or near-real-time analysis.
c) Variety: Data comes in
diverse formats, including structured, unstructured, and semi-structured data.
d) Veracity: The accuracy and
reliability of data are crucial for meaningful analysis.
e) Value: Extracting valuable
insights from big data can drive informed decision-making and business growth.
- Write
about the features of OOPS.
Ans:
Object-Oriented Programming (OOP)
is a programming paradigm based on the concept of objects, which contain both
data (attributes) and methods (functions).
Some characteristics(features) of
OOP are as follows:
1) Class:
A class is a blueprint or template
for creating objects. It defines a set of properties (attributes) and methods
(functions) that the objects created from the class will have.
2) Object:
An object is an instance of a
class. It is a specific realization of a class with actual values for the
properties defined by the class. Objects can interact with one another through
methods, making them the building blocks of an application.
3) Polymorphism:
Polymorphism refers the ability of
an object to take on different forms depending upon situations. The same
method(function) can behave differently on different classes.
4) Inheritance: In
Object-Oriented Programming (OOP), inheritance is a fundamental
concept that allows a class (called a subclass or derived class) to inherit
properties and behaviours (methods and attributes) from another class (called a
superclass or base class).
5) Encapsulation:
Encapsulation is a fundamental
concept in Object-Oriented Programming (OOP) that involves wrapping(bundling)
data (attributes) and methods (functions) into a single unit (class) and hides
the internal details from the outside world.
6) Abstraction:
Abstraction involves hiding the
complex implementation details and showing only the essential features of the
object.
- Explain
the prototype model of software development with a clear diagram.
Ans:
The Prototype Model is a software
development model in which a working prototype (an early sample or incomplete
version of the final product) is built, tested, and improved based on user
feedback, before the final system is developed. This model is especially useful
when the requirements of the system are not well understood from the beginning.
Key Phases of the Prototype Model
are as follows:
1.
Requirements Gathering: Basic system
requirements are gathered from the client.
2.
Quick Design: A basic layout/UI or conceptual
design is made to show how the system might look.
3.
Build Prototype: A functional but limited
version of the software is built.
4.
Customer Evaluation of Prototype: The prototype
is shown to the customer.
5.
Refine Requirements Incorporating Customer
Suggestions: Feedback from the customer is used to improve the prototype.
This loop continues until the
customer is satisfied and approves the prototype.
Group 'C'
Long answer questions: [8
x 2 = 16]
15. What is
network topology? Explain any three topologies with their merits and demerits.
- Define
a user-defined function with an example. Write a program to test if a
number is prime or composite.
Ans:
#include <stdio.h>
#include <conio.h>
void check(int);
void main() {
int a;
clrscr();
printf("Enter a number: ");
scanf("%d", &a);
check(a);
getch();
}
void check(int x)
{
int i, count = 0;
if (x <= 1)
{
printf("%d is neither PRIME nor
COMPOSITE", x);
return;
}
for (i = 1; i <= x; i++)
{
if (x % i == 0)
count++;
}
if (count == 2)
printf("%d is a PRIME
number", x);
else
printf("%d is a COMPOSITE
number", x);
}
OR
What is a file? Write about the
modes of operation in file handling? WAP that writes into a file named
myfile.docx character wise.
Ans:
A file is a collection of related
data stored on a disk. It allows data to be saved permanently so it can be
accessed and processed later, even after the program is closed. In C programming,
file handling enables reading from and writing to files using a set of standard
library functions.
There are mainly six modes, these
modes are used with the fopen() function, which opens a file and returns a
pointer to that file.
The various file handling (opening)
modes in C are as follows:
1)
"r" mode (Read): "r"
mode opens an existing file for the purpose of reading only. The possible
operation is reading from the file.
2)
"w" mode (Write): "w"
mode opens a file for the purpose of writing only. The possible operation
is writing to the file.
3)
"a" mode (Append): "a"
mode opens an existing file for the purpose of appending (i.e., adding new
information at the end of file).
4)
"r+" mode (Read + Write): "r+"
mode opens an existing file for the purpose of both reading and writing.
5)
"w+" mode (Write + Read): "w+"
mode opens a file for the purpose of both writing and reading.
6)
"a+" mode (Append + Read): "a+"
mode opens an existing file for the purpose of both reading and appending.
A program that writes into a file
named myfile.docx character wise are as follows:
#include<stdio.h>
#include<conio.h>
void main()
{
char name[20];
int rn, age;
FILE *fptr;
clrscr();
fptr=fopen("myfile.docx","w");
printf("Enter name:");
scanf("%s",name);
printf("Enter rollno:");
scanf("%d",&rn);
printf("Enter age:");
scanf("%d",&age);
fprintf(fptr,"\n%s\t%d\t%d",name,rn,age);
fclose(fptr);
getch();
}
posted by Computer with Madhav @ April 12, 2025
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