Students can access the CBSE Sample Papers for Class 12 Computer Science with Solutions and marking scheme Term 2 Set 5 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 5 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.
Define stack.
Answer:
A stack is a data structure that allows addition and removal of elements in a particular order. Every time; an element is added, it goes on the top of the stack and the only element that can be removed is the element that was at the top of the stack.

Question 2.
(i) Expand the following
FTP, VoIP
Answer:

  • FTP – file Transfer Protocol.
  • VoIP – Voice over Internet Protocol.

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 5 with Solutions

(ii) Which type of network out of LAN, PAN and MAN is formed, when you connect two mobiles using Bluetooth to transfer a video?
Answer:
PAN (Personal Area Network).

Question 3.
What is table? Also, define Candidate Key. BD
Answer:
A table consists of a number of rows and columns. Each record contains values for the attributes. A candidate key is the smallest subset of the super key for which there does not exist a proper subset; that is super key. In other words, all attribute combinations inside a relation that can serve as primary key are candidate keys.

Question 4.
Consider the following statement and answer the following questions cursor, rowcount
(a) What is row count ?
Answer:
The rowcount is a property of cursor object that returns the number of rows retrieved from the; cursor so far.

(b) Where is row count used ?
Answer:
rowcount is used frequently in the loops to prevent the infinite loops.

Question 5.
Write output for SQL queries (a) to (d), which are based on the table: STUDENT given below:
Table: STUDENT

ItemNo  Item Scode Qty Rate LastBuy
2005 Sharpener Classic 23 60 8 31-Jun-09
2003 Ball Pen 0.25 22 50 25 01-Feb-10
2002 Gel Pen Premimum 21 150 12 24-Feb-10
2006 Gel Pen Classic 21 250 20 11-Mar-09
2001 Eraser Small 22 220 6 19-Jun-09
2004 Eraser Big 22 110 8 02-Dec-09
2009 Ball Pen 0.5 21 180 18 03-Nov-09

(a) SELECT COUNT(DISTINCT Scode) FROM STORE;
Answer:
COUNT(DISTINCT Scode)
3

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 5 with Solutions

(b) SELECT Rate* Qty FROM STORE WHERE ItemNo=2004;
Answer:
Rate* Qty
880

(c) SELECT MAX(Qty) FROM STORE;
Answer:
AX(Qty) s
250

(d) SELECT SUM(Rate) FROM STORE WHERE Scode=22;
Answer:
SUM(Rate):
39

Question 6.
(a) What is primary key?
Answer:
A primary key is a set of one or more attributes that can uniquely identify the relation.

(b) What is My SQLdb?
Answer:
MySQLdb is an interface for connecting to a MySQL database server from Python.

Question 7.
Observe the following table Pro_Info carefully:

PID PNAME QTY PRICE COMPANY SUPCODE
101 DEGITAL CAMERA 14X 120 12,000 RENBIX SOI
102 DIGITAL PAD lli 100 22,000 DIGI POP S02
104 Stapler Medium 500 1,100 STOREKING SOI
106 Punching Machine Big 70 28,000 DISPEXPERTS S02
105 Stapler Mini 60 12,000 MOVEON S03

(a) Identify the primary key of above table.
Answer:
PID

(b) Identify the candidate key(s) of above table.
Answer:
PID, PNAME

OR

(c) Identify the degree and cardinality of table PRODUCT.
Answer:
Degree: 6

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 5 with Solutions

(d) Which command is used to remove the tuples from the table?
Answer:
DELETE

Section – B
[3 Marks Each]

Question 8.
Write a python program to demonstrate implementation of stack using lists with proper documentation.
OR
Write an algorithm to convert infix to postfix.
Answer:
# Python program to
# demonstrate stack implementation
# using list stack = []
# append ( ) function to push
# element in the stack
stack, append (‘a’) stack, append (‘d’) stack, append (‘c’) print (‘Initial stack’) print (stack)
# pop ( ) function to pop
# element from stack in
# LIFO order
print (‘\ nElements popped from stack : ‘) print (stack . pop ( ))
print (stack . pop ( ) )
print (stack . pop ( ))
print (‘\nStack after elements are popped :’) print (stack)
# uncommenting print (stack, pop ( ))
# will cause an IndexError
# as the stack is now empty

OR

1. Scan the infix expression from left to right.
2. If the scanned character is an operand, output it.
3. Else,
(i) If the precedence of the scanned operator is greater than the precedence of the operator in the stack (or the stack is empty or the stack contains a ‘(‘), push it.

(ii) Else, Pop all the operators from the stack which are greater than or equal to in precedence than that of the scanned operator. After doing that Push the scanned operator to the stack. (If you encounter parenthesis while popping then stop there and push the scanned operator in the stack.)

(iii) Else, Pop all the operators from the stack which are greater than or equal to in precedence than that of the scanned operator. After doing that Push the scanned operator to the stack. (If you encounter parenthesis while popping then stop there and push the scanned operator in the stack.)

4. If the scanned character is an'(‘, push it to the stack.
5. If the scanned character is an’)’, pop the stack and output it until a'(‘ is encountered, and discard both the parenthesis.
6. Repeat steps 2-6 until infix expression is scanned.
7. Print the output
8. Pop and output from the stack until it is not empty.

Question 9.
(a) Which clause is used to sort the records of a table?
Answer:
ORDER BY

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 5 with Solutions

(b) What is the SQL ?
Answer:
SQL refers to structured Query Language, a standard query language used by RDBMs to create, maintain and guery upon their databases.

Question 10.
Consider the structure of table Doctor given below:
Doctor_id(p)
Doctor_Name Hospital_id(F)
Joining_Date
Speciality
Salary
Experience
Write Python code to create the above table.
Answer:
import MySQLdb .
db = MySQLdb.connect(‘localhost’HosAdmin’,
‘HosAdmin0123′,’XYZHospital’ ) cursor=db.cursor()
cursor.execute (“DROP TABLE IF EXISTS DOCTOR”) sql=”””Create Table Doctor (‘Doctor_Id’ INT NOTNULL,
‘Doctor_Name’ Char(50) NOTNULL,
‘Hospital_Id’ INT NOTNULL,
‘Joining_Date’ Date NOTNULL,
‘Speciality’ Char (50),
‘Salary’ Float,
‘Experience’ Float,
Primary Key (‘Doctor_Id’))””” cursor.execute(sql) cursor.close() db.close()

Commonly Made Error:

  • Few students get confused to import the correct DB – API module.

Answering Tips:

  • Keep in mind to give user id and password while connecting to a database.
  • Be sure to import the correct DB – API module.

Section – C
( 5 Marks Each)

Question 11.
Write SQL queries for (a) to (d) which are based on the tables Trainer given below:
Table: VEHICLE

VCODE VEHICLE TYPE PERKM
V01 VOLVO BUS 150
V02 AC DELUXE BUS 125
V03 ORDINARY BUS 80
V05 SUV 30
V05 CAR 18

Table: TRAVEL

CNO CNAME TRAVEL DATE KM VCODE NOP
101 K. Niwal 2015-12-13 200 V01 32
103 Fredrick Sym 2016-03-21′ 120 V03 45
105 Hitesh Jain 2016-04-23 450 V02 42
202 Ravi Anish 2016-01-13 80 V02 40
207 John Malina 2015-02-10 65 V04 2
104 Sahanubhuti 2016-01-28 90 V05 4
106 Ramesh Jaya 2016-04-06 100 V01 25

Note:
PERKM is Freight Charges per kilometer.
Km is kilometres travelled.
NOP is number of passengers travelled in vehicle.
(a) To display CNO, CNAME, TRAVELDATE from the table TRAVEL in descending order of CNO.
Answer:
SELECT CNO, CNAME, TRAVELDATE FROM TRAVEL ORDER BY CNO DESC;

(b) To display the CNAME of all customers from the table TRAVEL who are travelling by vehicle with code V01 or V02.
Answer:
SELECT CNAME FROM TRAVEL WHERE VCODE = ‘V01 ‘ OR VCODE =’V02’;

(c) To display the CNO and CNAME of those customers from the table TRAVEL who travelled between ‘2015-12-31’ and ‘2015-05-01’.
Answer:
SELECT CNO, CNAME FROM TRAVEL WHERE TRAVELDATE > = ‘2015-05-01’ AND TRAVELDATE< = ‘2015-12-31’;

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 5 with Solutions

(d) To display the different vehicle code from table vehicle.
Answer:
SELECT DISTINCT VCODE FROM TRAVEL;

Commonly Made Error:

  • Some students do not write the ASC and DESC for increasing and decreasing order.

Answering Tip:

  • Remember to mention the order in which to order a field i.e., Ascending/Descending

Question 12.
(a) Write two advantages and disadvantages of bus topology.
OR
Define the following:
Wide Area Network, VoIP
Answer:
Advantages:

  • Easy to connect and install.
  • Involves a low cost and installation time.

Disadvantages:

  • The entire network shuts down if there is a failure in the connecting cable.
  • Only a single message can travel at a particular time.

OR

A Wide Area Network (WAN) is a network that exists over a large scale geographical area. A WAN connects different smaller networks, including local area networks (LANs) and metropolitan area networks (MANs) VoIP (Voice over Internet Protocol) is a methodology and group of technologies for delivering voice communications and multimedia sessions over IP networks, such as the Internet.

Commonly Made Error:

  • Some students get confused in different concept and write definition interchangeably.

Answering Tip:

  • Students should learn all the concepts very carefully.

(b) What do you mean by packet switching?
Answer:
Packet Switching transmits data across digital networks by breaking it down into blocks or packets for more efficient transfer using various network devices. Each time one device sends a file to another, it breaks the file down into packets so that it can determine the most efficient route for sending the data across the network at that time.

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 5 with Solutions

Question 13.
Perfect Edu Services Ltd. is an educational organization. It is planning to setup its India campus at Karnataka with its head office at Delhi.
The Karnataka Campus has 4 main buildings – ADMIN, ENGINEERING, BUSINESS and MEDIA. You as a network expert have to suggest the best network related solutions for their problems raised in (a) to (d), keeping in mind the distances between the buildings and other given parameters. Shortest distances between various buildings:

Admin to Engineering 55 mt
Admin to Business 90 mt
Admin to Media 90 mt
Engineering to Business 55 mt
Business to Media 45 mt
Delhi Head office to Karnataka campus 2175 km

Number of computers installed at various buildings are as follows:

Admin 110
Engineering 75
Business 40
Media 40
Media 12
Delhi Head office 20

(a) Suggest the most appropriate location of the server inside the Karnataka campus to get the best connectivity for maximum no. of computers.
Answer:
Admin (Due to maximum number of computers)

(b) Draw the cable layout to efficiently connect various buildings within the Karnataka campus for connecting the computers.
Answer:
CBSE Sample Papers for Class 12 Computer Science Term 2 Set 5 with Solutions 1

(c) Which hardware device will you suggest to be procured by the company to be installed to protect and control the internet uses within the campus?
Answer:
Firewall or Router

(d) Which will you suggest to establish the online face to face communication between the people in the admin office of Karnataka campus and Delhi Head office.
Answer:
Video Conferencing