CBSE Class 12 Informatics Practices Question Paper 2026 Solved Code 90

SECTION A

1. State whether the following statement is True or False : [1 Mark]
In Pandas Series, the Positional index can be a string or an integer.

Answer: False

Teacher's Note:
a) A positional index in Pandas is always an integer that shows the position of an element.
b) A string index is called a label index, not a positional index.

2. We can add a new row to a DataFrame DF using the ______ method. [1 Mark]
(A) DF.add()
(B) DF.loc[]
(C) DF.loc()
(D) DF.addloc[]

Answer: (B) DF.loc[]

Teacher's Note:
a) DF.loc[new_label] = [values] is used to add a new row with a chosen label.
b) Remember loc uses square brackets, not round brackets.

3. Naveen discarded various types of waste material without realizing that e-waste contains harmful substances that could pollute the environment. He wants to know which of the following will be considered as e-waste ? [1 Mark]
(A) Plastic Bottle
(B) Broken Smartphone
(C) Aluminium Foil
(D) Banana Peel

Answer: (B) Broken Smartphone

Teacher's Note:
a) E-waste means discarded electronic or electrical devices.
b) Plastic, aluminium foil and banana peel are not electronic items.

4. In which scenario is a bar chart preferred over a line chart ? [1 Mark]
(A) To visualise monthly temperature trends over a year.
(B) To compare the number of students in different classes.
(C) To show stock price movements over time.
(D) To analyse trends in website traffic over days.

Answer: (B) To compare the number of students in different classes

Teacher's Note:
a) Bar charts are best for comparing discrete categories.
b) Line charts are used to show trends over continuous time.

5. Which of the following network topology uses a central cable (backbone) to connect all devices ? [1 Mark]
(A) Mesh
(B) Star
(C) Tree
(D) Bus

Answer: (D) Bus

Teacher's Note:
a) In Bus topology, all devices are connected to a single central cable called the backbone.
b) Do not confuse Bus with Star, where a central device (hub/switch) is used instead of a cable.

6. State whether the following statement is True or False : [1 Mark]
In SQL, an aggregate function returns multiple values for each column on which it is applied.

Answer: False

Teacher's Note:
a) An aggregate function like SUM, AVG, COUNT returns a single summary value for a column.
b) Do not confuse aggregate functions with GROUP BY, which can give multiple groups of single values.

7. Rohini has developed a new kind of water purifier that uses a unique filtration method. Which type of Intellectual Property Right should she apply to protect her invention ? [1 Mark]
(A) Trademark
(B) Copyright
(C) Patent
(D) Both Copyright & Trademark

Answer: (C) Patent

Teacher's Note:
a) A Patent protects a new invention or process.
b) Trademark protects brand names/logos, and Copyright protects creative works like books and music.

8. Aditya is working on a DataFrame named df. He has written the statement :
print(df.loc['S2'])
What will the above statement do ? [1 Mark]
(A) Display the data of the row having label 'S2'.
(B) Display the columns of the DataFrame.
(C) Display the data type of the column having label 'S2'.
(D) Display the index numbers of the DataFrame.

Answer: (A) Display the data of the row having label 'S2'.

Teacher's Note:
a) loc[] is used for label based indexing on rows.
b) Remember iloc[] is used for position based indexing.

9. What will be the result of the following SQL command ? [1 Mark]
SELECT LENGTH ('Data Base');
(Note : There is single space between the words Data and Base.)
(A) 7
(B) 8
(C) 9
(D) Error

Answer: (C) 9

Teacher's Note:
a) LENGTH() counts all characters, including spaces.
b) "Data Base" has 4 + 1 + 4 = 9 characters.

10. Which of the following is a key feature of a Static Web Page ? [1 Mark]
(A) Its content updates very frequently.
(B) It displays different content to different users.
(C) It loads slower than a Dynamic Web Page.
(D) It shows the same content unless the code is manually updated.

Answer: (D) It shows the same content unless the code is manually updated.

Teacher's Note:
a) Static pages have fixed content stored as plain HTML files.
b) Dynamic pages generate content on the fly based on user or database input.

11. Which of the following is the correct expanded form of DML ? [1 Mark]
(A) Device Management Language
(B) Device Manipulation Language
(C) Data Management Language
(D) Data Manipulation Language

Answer: (D) Data Manipulation Language

Teacher's Note:
a) DML includes commands like INSERT, UPDATE, DELETE and SELECT.
b) DDL (CREATE, ALTER, DROP) is different from DML.

12. CSV stands for __________ Separated Values. [1 Mark]
(A) Colon
(B) CTRL
(C) Comma
(D) Caret

Answer: (C) Comma

Teacher's Note:
a) CSV = Comma Separated Values.
b) Each field in a CSV row is separated by a comma.

13. Which of the following is an example of maintaining good net etiquette ? [1 Mark]
(A) Spamming emails or messages to strangers.
(B) Ignoring other's opinions in online discussions.
(C) Not using copyrighted materials without permission of the owner.
(D) Sharing someone's private information publicly.

Answer: (C) Not using copyrighted materials without permission of the owner.

Teacher's Note:
a) Good net etiquette means respecting others' rights and privacy online.
b) Spamming and sharing private data without consent are violations of net etiquette.

14. In the context of creating a Pandas Series from a dictionary, which of the following statement is correct ? [1 Mark]
(A) The values of the dictionary become the indices of the Series.
(B) The keys of the dictionary become the values of the Series.
(C) The keys of the dictionary become the indices of the Series.
(D) The Series will have default integer indices starting from 0, ignoring the dictionary keys.

Answer: (C) The keys of the dictionary become the indices of the Series

Teacher's Note:
a) Dictionary keys map directly to the Series index labels.
b) Dictionary values become the corresponding data values of the Series.

15. In Pandas, when extracting a portion of a Series ser1 using ser1[start:end] with positional indices start and end, which of the following statements is true ? [1 Mark]
(A) The element at the end index is included in the output.
(B) The element at the end index is excluded from the output.
(C) The elements at both the start and end indices are excluded from the output.
(D) The element at the start index is excluded from the output.

Answer: (B) The element at the end index is excluded from the output.

Teacher's Note:
a) Positional slicing in Python follows the "end excluded" rule, same as list slicing.
b) The start index element is always included in the output.

16. Nisha is using an Android app to make a voice call over the internet to her friend in another country. Which protocol is being used in this case ? [1 Mark]
(A) Chat
(B) VoIP
(C) Email
(D) TV

Answer: (B) VoIP

Teacher's Note:
a) VoIP stands for Voice over Internet Protocol, used for internet voice calls.
b) Chat and Email are text based services, not voice calls.

17. State whether the following statement is True or False : [1 Mark]
The INSTR(string1, string2) function in SQL returns 0 if string2 is not present as a substring in string1.

Answer: True

Teacher's Note:
a) INSTR() returns the position of the first occurrence of string2 in string1.
b) If string2 is not found, INSTR() returns 0.

18. In a Pandas DataFrame, which value for axis will be used to delete a column ? [1 Mark]
(A) axis = -1
(B) axis = 0
(C) axis = 1
(D) axis = 2

Answer: (C) axis = 1

Teacher's Note:
a) axis = 1 refers to columns and axis = 0 refers to rows in Pandas.
b) Remember: "1 for column, 0 for row" is a quick way to recall this rule.

19. What will be the result of the following SQL command ? [1 Mark]
SELECT ROUND(15.678, 2);
(A) 15.00
(B) 15.67
(C) 15.68
(D) 16.00

Answer: (C) 15.68

Teacher's Note:
a) ROUND(number, decimals) rounds a number to the given number of decimal places.
b) 15.678 rounded to 2 decimal places becomes 15.68 as the third decimal digit is 8, which rounds up.

20. Assertion (A) : Pandas DataFrame can store values of multiple data types in multiple Columns. [1 Mark]
Reason (R) : DataFrames are implemented using 2D arrays, which allows only numeric values.
(A) Both (A) and (R) are True, and (R) correctly explains (A).
(B) Both (A) and (R) are True, but (R) does not correctly explain (A).
(C) (A) is True, but (R) is False.
(D) (A) is False, but (R) is True.

Answer: (C) (A) is True, but (R) is False.

Teacher's Note:
a) DataFrames can store multiple data types across different columns, so (A) is correct.
b) DataFrames are not restricted to only numeric values, so (R) is false.

21. Assertion (A) : The output of the SQL query SELECT COUNT(name) FROM students; will differ from the output of SELECT COUNT(*) FROM students; if there are some NULL values in the name column. [1 Mark]
Reason (R) : COUNT(column_name) returns the count of NON NULL values in that column, whereas COUNT(*) returns the number of records in the table.
(A) Both (A) and (R) are True, and (R) correctly explains (A).
(B) Both (A) and (R) are True, but (R) does not correctly explain (A).
(C) (A) is True, but (R) is False.
(D) (A) is False, but (R) is True.

Answer: (A) Both (A) and (R) are True, and (R) correctly explains (A).

Teacher's Note:
a) COUNT(column) ignores NULL values while COUNT(*) counts all rows.
b) This difference explains why the two queries can give different results when NULLs are present.

SECTION B

22. (a) List any two characteristics of Pandas library in Python. [2 Marks]

Answer:
1. Pandas works with tabular data structures like Series and DataFrame, making it easy to organise data.
2. It can handle missing data easily by detecting, filling or removing null values.

Teacher's Note:
a) Other valid points include fast performance on large datasets and support for reading/writing multiple file formats.
b) Any two correct characteristics are enough for full marks.

OR

(b) Briefly explain the purpose of Boolean Indexing with respect to DataFrames. Support your answer with a suitable example. [2 Marks]

Answer:
Boolean Indexing is used to filter and extract specific rows from a DataFrame based on a given condition. It returns only those rows where the condition evaluates to True.
Example: If df has a column 'Age', then df[df['Age'] > 30] will display only the rows where Age is greater than 30.

Teacher's Note:
a) The condition inside the square brackets must return a Series of True/False values.
b) A correct example with a condition is enough for full marks, even without showing full output.

23. Anjana had created a website using free design elements sourced from different creators online. She then published the site for public access but did not mention the source of the design elements used. [2 Marks]
(i) Identify one possible violation of IPR in this situation,
(ii) Name any two licensing models that allow legal reuse of digital creative work with conditions.

Answer:
1. Anjana has violated Copyright by not crediting the source of the design elements used.
2. Two licensing models that allow legal reuse with conditions are Creative Commons (CC) licenses and the GNU General Public License (GPL).

Teacher's Note:
a) Not mentioning the source of borrowed digital work is a common example of copyright infringement.
b) Open Source licensing is also accepted as a valid licensing model.

24. Define the following terms with respect to RDBMS : [2 Marks]
a. Domain
b. Tuple

Answer:
1. Domain is the set of all possible values that a column (attribute) can contain.
2. Tuple is a row in a table that represents one complete record.

Teacher's Note:
a) Domain restricts what type of data can go into a column, for example only numbers or only dates.
b) A table is made up of many tuples (rows) and attributes (columns).

25. (a) Explain the role of the following network devices in a network : [2 Marks]
(I) Modem
(II) Gateway

Answer:
1. Modem converts digital signals from a computer into analog signals for transmission and converts analog signals back into digital signals at the receiving end.
2. Gateway acts as a bridge or connecting point between two different types of networks, allowing them to communicate.

Teacher's Note:
a) MODEM stands for Modulator-Demodulator.
b) Gateway is needed when networks use different protocols or architectures.

OR

(b) Differentiate between add-ons and plug-ins in a web browser. [2 Marks]

Answer:
Add-ons enhance or customise the browser itself, such as adding features, blocking ads or managing passwords. Plug-ins are designed to enable the browser to handle specific types of content, such as Adobe Flash Player for playing certain media files.

Teacher's Note:
a) Add-ons change how the browser works or looks.
b) Plug-ins help the browser display or play specific content types it cannot handle natively.

26. Write SQL queries to perform the following : [2 Marks]
(I) Display the month (in numeric form) of the date '2026-01-01'.
(II) Display only the year part from the date '2026-01-01'.

Answer:
1. SELECT MONTH('2026-01-01');
2. SELECT YEAR('2026-01-01');

Teacher's Note:
a) MONTH() returns the numeric month value from a date.
b) YEAR() returns only the year part of a date value.

27. (a) What is data protection ? [2 Marks]
(b) Mention any two precautionary measures one can take to avoid the risk of cybercrime.

Answer:
1. Data protection refers to the practice of safeguarding data from unauthorized access, misuse, loss or damage.
2. Two precautions to avoid cybercrime are: using strong passwords and not sharing them, and avoiding clicking on suspicious links or emails.

Teacher's Note:
a) Other valid precautions include installing updated antivirus software and not sharing personal information online.
b) Focus on prevention steps rather than what cybercrime is, since that is asked separately elsewhere.

28. (a) Niharika wants to create a Pandas Series using a NumPy array with three elements 'a', 'b', and 'c', and assign custom indexes 'first', 'second' and 'third'. Help her complete the code below. [2 Marks]
import pandas as pd
import ______ as np
arr = np._____ (['a' , 'b' , 'c'])
s = pd._____(arr,_____=['first','second','third'])
print(s)

Answer:
import pandas as pd
import numpy as np
arr = np.array(['a', 'b', 'c'])
s = pd.Series(arr, index=['first', 'second', 'third'])
print(s)

Teacher's Note:
a) NumPy is always imported with the alias np.
b) The index parameter of pd.Series() is used to assign custom labels.

OR

(b) Write the output of the following code : [2 Marks]
import pandas as pd
s1 = pd.Series ([1, 2, 3], index = ['a','b','c'])
s2 = pd.Series ([4, 5, 6], index = ['b' , 'c', 'd'])
print (s1 + S2)

Answer:
a NaN
b 6.0
c 8.0
d NaN
(Note: The code has an error since S2 is written in uppercase in print(), while it was defined as s2 in lowercase, so this would actually raise a NameError in Python; but as per the marking scheme the addition output shown above is also accepted.)

Teacher's Note:
a) When adding two Series, only matching index labels get valid values; unmatched ones become NaN.
b) Common indices b and c get 2+4=6.0 and 3+5=8.0 respectively.

SECTION C

29. Mandeep received an email stating he won a lottery though he had never participated in any such event. He was asked to provide bank details to process the amount. Mandeep provided the required details but within next few minutes ` One lakh was debited from his account. [3 Marks]
Answer the following questions based on the given case study :
(i) Mandeep is the victim of which type of cybercrime ?
(ii) Other than email, mention any two common methods through which this type of cybercrime is being committed these days.
(iii) Name one law that safeguards the rights of Internet users in India.

Answer:
1. Mandeep is a victim of Phishing.
2. Two other common methods used for this cybercrime are SMS messages and voice calls (fake calls impersonating banks or officials).
3. The Information Technology (IT) Act, 2000 safeguards the rights of Internet users in India.

Teacher's Note:
a) Phishing tricks victims into revealing sensitive information like bank details.
b) Social media messages and fake websites are also accepted as valid methods.

30. (a) Write a Python program to create and display a Pandas Series as shown below : [3 Marks]
July 31
Aug 31
Sept 30
Oct 31
The index labels are the names of the months - July, Aug, Sept, Oct.
The corresponding scalar values are the number of days in these respective months - 31, 31, 30, 31.

Answer:
import pandas as pd
months = ['July', 'Aug', 'Sept', 'Oct']
days = [31, 31, 30, 31]
s = pd.Series(days, index=months)
print(s)

Teacher's Note:
a) The data list and index list must be in the same order and of equal length.
b) pd.Series(data, index) is the correct way to assign custom labels.

OR

(b) A CSV file named customer.csv contains records of customers. The first row of the file represents the header. Sample data from the file is shown below :
Name, Age, City
Rudra,17,Kolkata
Divya,19,Dehradun
Nabeel,22,Lucknow
Write a Python program to import data from the CSV file into a Pandas DataFrame named DF and display the last two rows. [3 Marks]

Answer:
import pandas as pd
DF = pd.read_csv("customer.csv")
print(DF.tail(2))

Teacher's Note:
a) read_csv() is used to import CSV file data into a DataFrame.
b) tail(2) displays the last two rows of the DataFrame.

31. (i) Write an SQL statement to create a table named PRODUCTS with the following specifications :
Column Name: PID | PName | PCat | Price
Data Type: Integer | Varchar of size 30 | Char of size 15 | Decimal Number
Key: Primary Key | | |
(ii) Write an SQL query to increase the price of all items by 100, whose product category is Grocery, in the table PRODUCTS. [3 Marks]

Answer:
1. CREATE TABLE PRODUCTS (PID INT PRIMARY KEY, PName VARCHAR(30), PCat CHAR(15), Price FLOAT);
2. UPDATE PRODUCTS SET Price = Price + 100 WHERE PCat = 'Grocery';

Teacher's Note:
a) PRIMARY KEY should be specified with the PID column while creating the table.
b) UPDATE with SET and WHERE is used to modify specific rows only.

32. (a) Consider the following tables : [3 Marks]
Table 1 : TEACHER, which stores Teacher ID (TID), Teacher Name (TName), Experience (Experience) and City (City) that they live in.
TID | TName | Experience | City
1 | Kartik | 5 | Bhopal
2 | Shahnaz | 6 | Nagpur
3 | Rajendra | 7 | Delhi
4 | Tanvi | 4 | Bhopal
5 | Alam | 9 | Delhi
Table 2 : SUBJECT, which stores Subject ID (SID), Subject Name (SubName) and ID of the teacher (TID) teaching that Subject.
SID | SubName | TID
101 | Physics | 1
102 | Chemistry | 2
103 | Mathematics | 3
104 | Informatics Practices | 4
105 | Computer Science | 5
Write appropriate SQL query for the following :
(I) Delete the record of the subject whose TID is equal to 4.
(II) Display the names of teachers who have more than 5 years of experience and who stay in Nagpur.
(III) Display subject names along with their teacher names.

Answer:
1. DELETE FROM SUBJECT WHERE TID = 4;
2. SELECT TName FROM TEACHER WHERE Experience > 5 AND City = 'Nagpur';
3. SELECT SubName, TName FROM SUBJECT, TEACHER WHERE SUBJECT.TID = TEACHER.TID;

Teacher's Note:
a) DELETE with WHERE removes only the matching row(s).
b) Joining two tables needs a common column, here TID, used in the WHERE clause or ON clause.

OR

(b) Consider the table LIBRARY as given below.
BookId | Title | Genre | Price
101 | Python Basics | Technology | 278
201 | The Silent Patient | Fiction | 340
301 | Data Science | Technology | 291
401 | Oceans | Marine Life | NULL
(I) Which attribute(s) can be considered as the Candidate key(s) ? Justify your answer.
(II) Write an SQL query to insert a new record with the following values :
BookId : 501
Title : AI for ALL
Genre : Technology
Price : 589
(III) Write an SQL query to add a new column Author that is a character data type of size 20. [3 Marks]

Answer:
1. BookId can be considered as the Candidate key because it has a unique value for every row of the table.
2. INSERT INTO LIBRARY VALUES (501, 'AI for ALL', 'Technology', 589);
3. ALTER TABLE LIBRARY ADD Author VARCHAR(20);

Teacher's Note:
a) A Candidate key must have unique, non-repeating values for every row.
b) ALTER TABLE ADD is used to add a new column to an existing table.

SECTION D

33. Ms. Anjali, a data analyst, has been assigned the task of creating a histogram to display the age distribution of ten participants in a workshop. She has been provided with the following list of their ages :
Ages = [22, 25, 24, 28, 30, 24, 29, 27, 21, 23]
She has started writing a Python program for it. However, the code is incomplete. Help her complete the program by filling in the missing parts, so that the histogram as shown below is displayed. [4 Marks]
import matplotlib.pyplot as plt
Ages = [22, 25, 24, 28, 30, 24, 29, 27, 21, 23]
binsize=[20,22,24,26,28,30]
plt.________(Ages, bins=binsize, edgecolor = 'black', label = 'Participants') # Statement-1
______.xlabel('Age') # Statement-2
plt.ylabel('Number of Participants')
plt.title("Age Distribution")
plt._______ # Statement-3
_________ # Statement-4
I. Statement-1 : write the suitable code which plots the histogram.
II. Statement-2 : fill in the blank with the correct alias of the required module to set the label on x axis.
III. Statement-3 : fill in the blank with the correct Python code to display the legend on the graph.
IV. Statement-4 : fill in the blank with the appropriate Python code to display the graph.

[Figure: A histogram titled "Age Distribution" with x-axis "Age" from 20 to 30 and y-axis "Number of Participants" from 0.0 to 3.0. Bars: 20-22 has height 1, 22-24 has height 2, 24-26 has height 3, 26-28 has height 1, 28-30 has height 3. A legend box labelled "Participants" is shown at the top left.]

Answer:
1. Statement-1: hist
2. Statement-2: plt
3. Statement-3: legend()
4. Statement-4: plt.show()

Teacher's Note:
a) plt.hist() is the correct function name for plotting a histogram.
b) plt.show() must be written with parentheses to actually display the graph window.

34. (a) Shalini, who works as a database designer in the hotel industry, has created a table named Guest to keep track of guest details as shown below : [4 Marks]
Table : Guest
GuestID | GuestName | RoomNumber | CheckInDate | Charges
G101 | Harish | 101 | 2025-04-03 | 3000
G102 | Sunita | 101 | 2025-04-03 | 3000
G103 | Ramesh | 102 | 2025-05-04 | 5000
G104 | Bhumika | 103 | 2025-06-02 | 3500
Write a suitable SQL query for the following :
I. Display last 3 characters of guest name in upper case.
II. Display the name of the guest along with the day name of check-in date.
III. Charges को 1000 से विभाजित करने पर शेषफल (remainder) प्रदर्शित करें ।
IV. Extract and display three characters, starting from the second character, of each guest name.

Answer:
1. SELECT UPPER(RIGHT(GuestName, 3)) FROM Guest;
2. SELECT GuestName, DAYNAME(CheckInDate) FROM Guest;
3. SELECT MOD(Charges, 1000) FROM Guest;
4. SELECT SUBSTR(GuestName, 2, 3) FROM Guest;

Teacher's Note:
a) RIGHT(string, n) extracts the last n characters, and UPPER() converts them to uppercase.
b) SUBSTR(string, start, length) is used to extract characters starting from a given position.

OR

(b) Consider the following table and write the output of the following SQL Queries.
Table : ORDERS
ORDERID | CUSTOMERNAME | TOTALAMOUNT | DISCOUNT | ORDERDATE
101 | Hemant | 5000 | 10 | 2024-03-01
102 | Neha | 7000 | 15 | NULL
103 | Keshav | 3000 | 5 | 2024-01-20
104 | Sandhya | 4500 | NULL | 2023-12-25
I. SELECT CUSTOMERNAME FROM ORDERS WHERE DISCOUNT IS NOT NULL;
II. SELECT CUSTOMERNAME, DISCOUNT FROM ORDERS WHERE DISCOUNT BETWEEN 5 AND 10;
III. SELECT MONTHNAME(ORDERDATE) FROM ORDERS WHERE ORDERDATE IS NOT NULL;
IV. SELECT ORDERID, DAY(ORDERDATE) FROM ORDERS; [4 Marks]

Answer:
1. Output of Query I: Hemant, Neha, Keshav
2. Output of Query II: Hemant - 10, Keshav - 5
3. Output of Query III: March, January, December
4. Output of Query IV: 101-1, 102-NULL, 103-20, 104-25

Teacher's Note:
a) DISCOUNT IS NOT NULL excludes the row where DISCOUNT is NULL (Sandhya's row).
b) DAY() applied on a NULL date value gives NULL as the output.

SECTION E

35. My Solutions Pvt. Ltd. is a reputed software development and IT consulting firm. The company's head office is located in Mysuru, and it has a regional office in Chennai. The Mysuru office comprises four departments: Human Resources, Research, Design and Technical Support. [5 Marks]
The distances between these departments and between Mysuru and Chennai are as follows :
Human Resources to Research: 55 metres
Human Resources to Design: 75 metres
Human Resources to Technical Support: 140 metres
Research to Design: 40 metres
Research to Technical Support: 80 metres
Design to Technical Support: 60 metres
Mysuru Office to Chennai Office: 350 kilometres
The number of computers in each department/office is as follows :
Human Resources: 30
Research: 80
Design: 50
Technical Support: 20
Chennai Office: 35
As a network engineer, you have to propose solutions for various queries listed from I to V.
I. Identify the most suitable department to install the main server in the Mysuru office. Justify your answer with a valid reason.
II. Create a cable layout design to establish Wired network connectivity between the departments in the Mysuru Office.
III. Suggest the appropriate network device to connect multiple computers within the Research department.
IV. What type of network (LAN, MAN, WAN) would best connect the Mysuru and Chennai office ?
V. Which device should be used if the signal strength weakens while transmitting data between the Human Resources and Technical Support departments due to the long distance between them ?

[Figure: A block diagram showing "Mysuru Head Office" as a large rectangle containing four smaller boxes labelled Human Resources, Research, Design and Technical Support. A separate oval labelled "Chennai Regional Office" is shown outside, connected conceptually to the Mysuru office.]

Answer:
1. The Research department is the most suitable place to install the main server because it has the maximum number of computers (80).
2. Cable layout: connect Human Resources, Design and Technical Support each directly to Research (which houses the server), forming a star like layout centred on Research.
3. A Switch (or Hub) should be used to connect multiple computers within the Research department.
4. A WAN (Wide Area Network) would best connect the Mysuru and Chennai offices since they are 350 kilometres apart.
5. A Repeater should be used to boost the weakened signal over the long distance between Human Resources and Technical Support.

Teacher's Note:
a) The server is usually placed in the department with the most computers to minimise average cable length and maximise efficiency.
b) WAN connects networks over very large geographical distances, unlike LAN which covers a small area.
c) A Repeater regenerates and amplifies a weak signal so it can travel longer distances without loss.

36. Consider the DataFrame Scholarship shown below : [3 + 1 + 1 = 5 Marks]
Name | Course | Amount
0 Ananya | B.Sc. | 62000
1 Karan | B.Tech | 67000
2 Simran | MCA | 64000
3 Rahul | BCA | 70000
4 Priya | BA | 69000
Answer the following questions :
I. Write Python code to create and display the given DataFrame using the Dictionary of Series method.
II. Rename row indexes to ['a', 'b', 'c', 'd', 'e']
III. Write Python statement to remove the last row of the given DataFrame

Answer:
1. import pandas as pd
name = pd.Series(["Ananya", "Karan", "Simran", "Rahul", "Priya"])
course = pd.Series(["B.Sc.", "B.Tech", "MCA", "BCA", "BA"])
amount = pd.Series([62000, 67000, 64000, 70000, 69000])
data = {"Name": name, "Course": course, "Amount": amount}
Scholarship = pd.DataFrame(data)
print(Scholarship)
2. Scholarship.index = ['a', 'b', 'c', 'd', 'e']
3. Scholarship = Scholarship.drop(Scholarship.index[-1])

Teacher's Note:
a) In the Dictionary of Series method, each column is created as a separate Series first, then combined into a dictionary.
b) Assigning a new list directly to DataFrame.index renames all row labels at once.
c) drop() with the last index position removes the last row of the DataFrame.

37. (a) Write suitable SQL query for the following : [5 Marks]
I. To display only the date part from the date/time expression '2026-01-01 10:10:10'
II. To convert all customer names from the Cust_Name column to lowercase in the Customer table.
III. To extract the first 4 characters from the City_Name column in Location table.
IV. To display the name of the city from the CITY column in EVENT table, after removing leading spaces.
V. To find the average salary from Salary column in Employees table.

Answer:
1. SELECT DATE('2026-01-01 10:10:10');
2. SELECT LOWER(Cust_Name) FROM Customer;
3. SELECT LEFT(City_Name, 4) FROM Location;
4. SELECT LTRIM(CITY) FROM EVENT;
5. SELECT AVG(Salary) FROM Employees;

Teacher's Note:
a) DATE() extracts only the date part from a datetime value.
b) LEFT(string, n) extracts the first n characters, while LTRIM() removes only leading spaces.

OR

(b) Write suitable SQL query for the following :
I. To display the value of \( 17^2 \).
II. To display the day part of the dates in the Hire_Date column of the Employee table.
III. To display the maximum value of the Bill_Amount column in the Bill table.
IV. To remove leading and trailing spaces from the Location column in the Branch table.
V. To display total salary from tot_sal column in Employees table. [5 Marks]

Answer:
1. SELECT POWER(17, 2);
2. SELECT DAY(Hire_Date) FROM Employee;
3. SELECT MAX(Bill_Amount) FROM Bill;
4. SELECT TRIM(Location) FROM Branch;
5. SELECT SUM(tot_sal) FROM Employees;

Teacher's Note:
a) POWER(x, y) or POW(x, y) calculates x raised to the power y.
b) TRIM() removes both leading and trailing spaces, unlike LTRIM() or RTRIM() which remove only one side.

Please click the link below to download pdf file of CBSE Class 12 Informatics Practices Question Paper 2026 Solved Code 90