CBSE Sample Papers for Class 12 Computer Science Term 2 Set 4 with Solutions

Students can access the CBSE Sample Papers for Class 12 Computer Science with Solutions and marking scheme Term 2 Set 4 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 4 with Solutions

Time: 2 Hours
Maximum Marks: 35

General Instructions:

The question paper is divided into 3 sections – A, B and C
Section A, consists of 7 questions (1 – 7). Each question carries 2 marks.
Section B, consists of 3 questions (8 – 10). Each question carries 3 marks.
Section C, consists of 3 questions (11 – 13). Each question carries 4 marks.
Internal choices have been given for question numbers 7, 8 and 12.

Section – A
(2 Marks Each)

Question 1.
Evaluate the following expressions:
(a) 6*3 + 4**2//5-8
Answer:
13

(b) 10 > 5 and 7 > 12 or not 18 > 3
Answer:
False

Question 2.
(i) Expand the following terms:
(a) PPP
Answer:
PPP : Point to Point Protocol

(b) FTP
Answer:
FTP : File Transfer Protocol

(ii) Name the transmission media best suitable for connecting to hilly areas.
Answer:
Microwave / Radio wave

Question 3.
What do you understand by Candidate Keys in a table? Give a suitable example of Candidate Keys from a table containing some meaningful data.
Answer:
A table may have more than one such attribute/group of attributes that identifies a tuple uniquely, all such attribute(s) are known as Candidate Keys.
Table: ITEM

Item_No	Item	_Qty
101	Pen	500
102	Pencil	700
104	CD	500
109	DVD	700
105	Eraser	300
103	Duster	200

In the above table Item, Item No can be candidates keys.

Question 4.
Differentiate between fetchone() and fetchall() methods with suitable example for each.
Answer:

fetchall() fetches all the rows of a query result.
An empty list is returned if there is no record to fetch the cursor. fetchone() method returns one row or a single record at a time. It will return None if no more rows/records are available.

Question 5.
Write the output of the queries (a) to (d) based on the table Student given below:
Table: STUDENT

Roll_No	Name	Class	DOB	Gender	City	Marks
1	Nanda	X	06-06-1995	M	Agra	551
2	Saurabh	XII	07-05-1993	M	Mumbai	462
3	Sonal	XI	06-05-1994	F	Delhi	400
4	Trisla	XII	08-08-1995	F	Mumbai	450
5	Store	XII	08-10-1995	M	Delhi	369
6	Marisla	XI	12-12-1994	F	Dubai	250
7	Neha	X	08-12-1995	F	Moscow	377
8	Nishant	X	12-06-1995	M	Moscow	489

(a) SELECT COUNT(*), City FROM STUDENT GROUP BY CITY HAVING COUNT(*)>1;
Answer:

COUNT(*)	City
2	Mumbai
2	Delhi
2	Moscow

(b) SELECT MAX(DOB),MIN(DOB) FROM STUDENT;
Answer:

MAX(DOB)
08-12-1995
MIN(DOB)
07-05-1993

NAME	GENDER
Sonal	F
store	M

(d) SELECT NAME, MARKS FROM STUDENT WHERE CITY IN (“MUMBAI”, “DELHI”)
Answer:

NAME	MARKS
Sarubh	462
Sonal	400
Trisha	350
Store	469

Question 6.
(a) In SQL, name the clause that is used to display the tuples in ascending order of an attribute.
Answer:
ORDER BY Clause

(b) In SQL, what is the use of IS NULL operator?
Answer:
To check if the column has null value / no value.

Question 7.
Observe the following table Pro_Info carefully:
Table: Pro_Info

ID	Product	Qty	Price	Transaction_Date
101	Plastic Floder 12″	100	3400	2014-12-14
104	Pen stand standard	200	4500	2015-01-31
105	Stapler Medium	250	1200	2015-02-28
109	Punching Machine Big	200	1400	2015-03-12
103	Stapler Mini	100	1500	2015-02-02

(a) Write the names of the most appropriate columns, which can be considered as candidate keys.
Answer:
Candidate keys : Id, Product

(b) Write the names of the most appropriate columns, which can be considered as primary key. Justify your answer.
Answer:
Primary key : Id, because it will uniquely identify each record in the table.

(a) Identify the degree and cardinality of the table Pro_info.
Answer:
Degree: 5, Cardinality: 5

(b) Consider the table TRANSPORT given below:
TRANSPORT

T_Code	ID	TType
T101	101	Bus
T102	104	Volvo
T103	105	Auto
T104	109	Train
T105	101	Truck
T106	103	Car

Which field will be consider as the foreign key if the tables Pro_Info and TRANSPORT are related in a database?
Answer:
Id

Sect ion – B
(3 Marks Each)

Question 8.
Write a function DeleteCustomer() to delete a Customer information from a list of CStack. The function delete the name of customer from the stack.
Or
Write a function to perform push and pop operations on a Stack containing Student details as given in the following
RNo integer
Name String
Age integer
Answer:
CStack = []
def DeleteCustomer(): if (CStack == [ ]) :
print(“There is no Customer!”) else:
print(“Record deleted:”,CStack.pop()) 3

defstkPUSH(stk,item): stk.append(item) top=len(stk)-1 defstkPOP(stk): ifstk!=[]:
returnstk.pop()
else:
return None

Question 9.
(a) A table, “Customers” has been created in a database with the following fields:
CustomerlD, CustomerName, ContactName, Address City, PostalCode, Country Give the SQL command to updates the first customer (CustomerlD = 1) with a new contact person “Rachit” and a new city “Mumbai”.
Answer:
UPDATE Customers
SET ContactName = ‘Rachit’, City= ‘Mumbai’
WHERE CustomerlD = 1;

(b) What is the use of wildcard ? Give an example
Answer:
The wildcard operators are used with the LIKE operator to search a value similar to a specific pattern in a column. There are 2 wildcard operators.
% (Percent) – represents 0,1 or many characters
_ (Underscore) = represents a single number or character For example: Select * from Customer where name like ‘S%’;
This command will show all those records from table named Customer where name field contains values starting with S for e.g. Sri, Siya, Shyam, Suman, etc.

Question 10.
Sonakshi has to create a database named Publishers in MYSQL.
She now needs to create a table named Book in the database to store the records of various Books.
The table Book has the following structure:

Field Name	Data type	Remarks
BookCode	Char(3)	primary key
Book_Name	Char(30)
Pages	Integer
Price	Integer
Authbr_Name	Char(30)

Help her to complete the task by suggesting appropriate SQL commands.
Answer:
CREATE DATABASE Publishers;
CREATE TABLE Book (
Book_Code CHAR(5)PRIMARY KEY
f
Book_Name CHAR(30),
Pages INT,
Price INT,
Author_Name CHAR(30)
);

Section – C
(5 Marks Each)

Question 11.
Write queries (a) to (d) based on the tables TRAINER and COURSE given below:
TRAINER

TID	TNAME	CITY	HIREDATE	SALARY
101	Sunaina	Mumbai	1998-10-15	90,000
102	Anamika	Delhi	1994-12-24	80,000
103	Deepti	Chandigarh	2001-12-21	82,000
104	Meenakshi	Delhi	2002-12-25	78,000
105	Richa	Mumbai	1996-01-12	95,000
106	Maniprabha	Chennai	2001-12-12	69,000

COURSE

CID	CNAME	FEES	STARTDATE	TID
c201	AGDCA	12,000	2018-07-02	101
c202	ADCA	15,000	2018-07-15	103
c203	DCA	10,000	2018-10-01	102
c204	DDTP	9,000	2018-09-15	104
c205	DHN	20,000	2018-08-01	101
c206	O LEVEL	18,000	2018-07-25	105

(a) Display the Trainer Name, City & Salary in descending order of their Hiredate.
Answer:
SELECT TNAME, CITY, SALARY FROM TRAINER ORDER BY HIREDATE DESC;

(b) To display the TNAME and CITY of Trainer who joined the Institute in the month of December 2001.
Answer:
SELECT TNAME, CITY FROM TRAINER WHERE HIREDATE BETWEEN ‘2001-12- 01’ AND ‘2001-12-31’;

(d) To display TNAME, HIREDATE, CNAME, STARTDATE from tables TRAINER and COURSE of all those courses whose FEES is less than or equal to 10000.
Answer:
SELECT TNAME,HIREDATE,CNAME, STARTDATE FROM TRAINER, COURSE WHERE
TRAINER.TID=COURSE.TID AND FEES<= 10000;

Question 12.
(a) Write two characteristics of Wi-Fi.
OR
Define the following:
HTML, XML
Answer:

It is wireless network.
It is used for short range.

HTML (Hyper Text Markup Language): It is a markup language that describes the structure and behavior of a web page. This language is used to create web pages.
XML (Extensible Markup Language): It is a meta language that provides a framework to define the markup language.

(b) Explain the purpose of a router
Answer:
A router establishes connection between two networks and it can handle network with different protocols. Using a routing table, routers make sure that the data packets are travelling through the best possible paths to reach their destination.

Question 13.
Delhi University of India is starting its first campus Nagarjun Nagar of South India with its centre admission office in Mumbai. The university has three major branch comprising of Administrative Branch, Theory Branch and Practical Branch in the 5 km area campus.
As a network expert, you need to suggest the network plan as per (a) to (d) to the authorities keeping in mind the distance and other given parameters.

Expected wire distances between various locations:

Administrative Branch to Theory Branch	90 m
Administrative Branch to Practical Branch	80 m
Theory Branch to Practical Branch	15 m
Admission Office Mumbai to Nagarjun Campus	1600 km

Expected number of computers to installed at various locations in the university are as follows:

Administrative Branch	15
Theory Branch	40
Practical Branch	150
Admission Office Mumbai	10

(a) Suggest the authorities, the cable layout amongst various branches inside university campus for connecting the branches.
Answer:
The suggested cable layout amongst various blocks inside university campus for connecting the
blocks will be as follow:

(b) Suggest the most suitable place (i.e. branch) to house the server of this university with a suitable reason.
Answer:
Practical Branch, because in this branch there are maximum number of computer and according to 80 – 20 rule of 80% traffic should be local.

(c) Suggest an efficient device from the following to be installed in each of the branch to connect all the computers.
(i) Switch
(ii) Modem
(iii) Gateway
Answer:
Switch

(d) Suggest the most suitable (very high speed) service to provide data connectivity between Admission Office located in Mumbai and Nagarjun Nagar campus from the following options:
(i) Telephone lines
(ii) Fixed line dial-up connection
(iii) Co-axial cable network
(iv) GSM
(v) Leased lines
(vi) Satellite connection
Answer:
Satellite connection