Students must start practicing the questions from CBSE Sample Papers for Class 11 Informatics Practices with Solutions Set 4 are designed as per the revised syllabus.
CBSE Sample Papers for Class 12 Informatics Practices Set 4 with Solutions
Time Allowed: 3 hours
Maximum Marks: 70
General Instructions:
- All questions are compulsory.
- Answer the questions after carefully reading the text.
- Student has to answer only one question where choice is given.
- All programming questions have to be answered with respect to Python only.
- In Python indentation is mandatory; however, number of spaces used for indenting may vary. In SQL related
- questions – semicolon should be ignored for terminating the SQL statements.
- Use of calculators is not permitted.
SOLVED
Multiple Choice Question:
Question 1.
(i) Which of the following is not an operating system?
(A) Windows
(B) Linux
(C) Oracle
(D) DOS
Answer:
(C) Oracle
Explanation: Some examples of operating systems include Apple macOS, Microsoft Windows, Google’s Android OS, Linux Operating System, and Apple iOS. Apple macOS is found on Apple personal computers such as the Apple Macbook, Apple Macbook Pro and Apple Macbook Air [1]
(ii) The ______ clause can occur with an if as well as with loops.
(A) else
(B) break
(C) continue
(D) None of these
Answer:
(A) else
Explanation: An else statement can be combined with an if statement. An else statement contains the block of code that executes if the conditional expression in the if statement resolves to 0 or a FALSE value. [1]
(iii) The system hides certain details of how data is stored, created and maintained. This statement belongs to: [1]
(A) Data Abstraction
(B) Data Updating
(C) Data Storing
(D) Data Concept
Answer:
Option (A) is correct.
Explanation: Abstraction is defined as an act of representing essential features without including background details [1]
(iv) SELECT statement is the type of- [1]
(A) Transaction Control Language
(B) Data Manipulation Language
(C) Data Definition Language
(D) None of these
Answer:
(B) Data Manipulation Language
Explanation: A data manipulation language is one which allows user to access or manipulate data. [1]
(v) A ______ is an unmanned aircraft which can be remotely controlled or can fly autonomously through software-controlled flight plans in their embedded systems, working in conjunction with on board sensors and GPS. [1]
(A) Drone
(B) Cyborg
(C) Humanoids
(D) None of these
Answer:
(A) Drone
Explanation: An unmanned aerial vehicle, commonly known as a drone, is an aircraft without any human pilot, crew or passengers on board. UAVs are a component of an unmanned aircraft system, which include additionally a ground-based controller and a system of communications with the UAV. [1]
Question 2.
(a) Why are language processors required? [1]
Answer:
(a) The programs written in High Level Language (HLL) need to be converted into machine understandable form. This is done with the help of language processors. [1]
(b) Explain device driver. [2]
Answer:
As the name signifies, the purpose of device deriver is to ensure proper functioning of a particular device. When it comes to the overall working of a computer system, the operating system does the work. It is not possible for operating system alone to manage all of the existing and new peripherals where each device has diverse characteristics. [2]
(c) Name the categories of compact disc (CD). [2]
Answer:
CD are categorized into three main formats as:
(i) CD-ROM (Compact Disc-Read Only Memory)
(ii) CD-R (Compact Disc-Recordable)
(iii) CD-RW (Compact Disc-Rewritable) [2]
(d) Explain data deletion and recovery. [4]
OR
What do you mean by software? Also, give purpose of software.
Answer:
One of the biggest threats associated with digital data is its deletion. The storage devices can malfunction or crash down resulting in the deletion of the stored data. Deleting digitally stored data means changing the details of data at bit level, which can be very time consuming. Therefore, when any data is simply deleted, its address entry is marked as free and that much space is shown as empty to the user, without actually deleting the data.
In case data gets deleted corrupted or accidentally, there arises a need to recover the data. Recovery of the data is possible only if the contents/memory space marked as deleted have not been overwritten by some other data. Data recovery is a process of retrieving deleted corrupted and lost data from secondary storage devices. [4]
OR
Software is a set of computer programs, procedures and associated documentation concerned with the operation of a data processing system. Software, commonly known as a set of programs, consists of all the required instructions that tell the hardware how to perform a particular task. Software is not only the basic requirement of a computer system but it makes a computer more powerful and useful. Purpose of software.
The purpose of software is to make computer hardware useful and operational. A software knows how to make different hardware components of a computer work and communicate with each other as well as with the end user. We cannot talk to or instruct the hardware of a computer directly. Hence, software acts as an interface between human users and the hardware.
Question 3.
(a) Write the advantage of interactive mode. [1]
Answer:
(a) Helpful when your script is extremely short and you want immediate results. [1]
(b)How will you convert ‘895’ taken as input from raw_input( ) (i) integer (ii) float and store it in a variable num.[1]
Answer:
(i) num = int (‘895’)
(ii) num = float (‘895′) [1]
(c) Write the Output
x = 5
y = -x
print (y) [1]
Answer:
-5
(d) Which statement is used to check if the letter’m’ is present in the word ‘Program’? [1]
Answer:
(d) ‘m ‘ in ‘Program’ [1]
(e) Write a Python program to calculate the length of a string. [2]
OR
Write a program which will find all such numbers which are divisible by 8 but are not a multiple of 5, between 500 and 1000 (both included). [2]
Answer:
str=input(“Enter the string:”)
count = 0
for char in str:
count +=1
print(“Length of string:”, count) [2]
list = [ ]
for i in range (500, 1001) :
if (i % 8 ==0) and (i % 5 ! = 0) :
list. append (str (i))
print (list) [2]
(f) Describe dict.fromkeys( ) with example. [4]
Answer:
The method fromkeys( ) creates a new dictionary with keys from seq and values set to value.
Syntax
dict.fromkeys{seq[, value]}
Parameters :
> seq – This is the list of values which would be used for dictionary keys preparation.
> value – This is optional , if provided then value would be set to this values.
Return Value
This method returns the list.
Example :
The following example shows the usage of fromkeys( ) method.
# !/user/bin/python
seq = {‘name’, ‘age’, ‘sex’}
dict = dict.fromkeys(seq)
print ” New Dictionary : %s” %
str(dict)
dict = dict.fromkeys(seq, 10)
print “New Dictionary : %s” %
str(dict)
Let us compile and run the above program, this will produce the following result:
New Dictionary : {‘age’ : None, ‘name’ : None, ‘sex’: None}
New Dictionary : {‘age’ : 10, ‘name’ : 10, ‘sex’ : 10} [4]
Question 4.
(a) Help Seema in predicting the output of the following queries: [3]
(i) SELECT (4*6-2+2*1) AS ‘FINAL’;
(ii) SELECT (10/2+4*2) AS ‘RESULT’;
(iii) SELECT (3+5*2-1*2) AS ‘PRINT’;
Answer:
(i) FINAL 24
(ii) RESULT 13
(iii) PRINT 11 [3]
(b) A school has a rule that each student must participate in a sports activity. So each one should give only one preference for sports activity. Suppose there are five students in a class, each having a unique roll number. The class representative has prepared a list of sports preferences as shown below.
Answer the following: [3]
Table: Sports Preferences
| RollNO. | Preference |
| 9 | Cricket |
| 13 | Football |
| 17 | Badminton |
| 17 | Football |
| 21 | Hockey |
| 24 | NULL |
| NULL | Kabaddi |
(i) Roll no. 24 may not be interested in sports. Can a NULL value be assigned to that student’s preference field ?
(ii) Roll no. 17 has given two sport preferences. Which property of relational DBMS is violated here? Can we use any constraint or key in the relational DBMS to check against such violation, if any?
(iii) Kabaddi was not chosen by any student. Is it possible to have this tuple in the Sports Preferences relation?
Answer:
(i) No, a NULL value can not be assigned to that student preference field according to the school’s rule.
(ii) Property 2 is violated here because each student must give only one preference.
(iii) No it is not possible to have this tuple in the sports preferences relation because Roll_no is primary key and primary key does not allow NULL values. [3]
(c) Give the terms for each of the following: [3]
(i) An attribute which can uniquely identify tuples of the table but is not defined as primary key of the table.
(ii) Software that is used to create, manipulate and maintain a relational databe.
(iii) It acts as an interface between the user and the database
Answer:
(i) Alternate key
(ii) DBMS (Database Management System)
(iii) Software [3]
(d) Compared to a file system, how does a database management system avoid redundancy in data through a database? [4]
Answer:
The file based data management systems contained multiple files that were stored in many different locations in a system or even across multiple systems. Because of this, there were sometimes multiple copies of the same file which lead to data redundancy. This is prevented in a database by database management system as there is a single database and any change in it is reflected immediately.
Because of this, there is no chance of encountering duplicate data. In file system, most of the time some data was stored repeatedly across the files. This can be avoided in DBMS is breaking such duplicate data into different tables and creating relations among them [4]
Question 5.
(a) Give any property of database. [1]
OR
Write the SQL query to fetch unique value of DEPARTMENT from WORKER table. [1]
Answer:
(a) A database is integrated as well as shared. [1]
OR
SELECT distinct DEPARTMENT From WORKER; [1]
(b) Define the following terms.
(i) Foreign key (ii) Domain [2]
Answer:
(i) In a relation, column whose data values correspond to the values of a key column in another relation is called foreign key.
(ii) Domain is defined as the set of all unique values permitted for an attribute. [2]
(c) Write command to create table Project whose fields are: [2]
| P_ID | varchar |
| Name | char |
| Start_date | date |
| End_date | date |
| No_of_candidate | int |
Answer:
CREATE TABLE Faculty (P_ID varchar(5) primary key,
Name char(20),
Start_date date,
End_date date,
No_of_candidate int
); [2]
(d) From table Project in Q. No. (5) (c), answer the following questions: [2]
(i) Identify the primary key
(ii) Identify the alternate key
Answer:
(i) P_ID
(ii) Name [2]
(e) Explain about Relational Model Terminology. [4]
Answer:
Relational Model Terminology :
(i) Attribute: In a database management system (DBMS) an attribute refers to a data base component such as table columns. It also may refer to a database field. Attribute describe the instance in the row of database. E.g. Student, Roll no., Name, etc.
(ii) Relation: It is sometimes used to refer to a table in a relational database but is more commonly used to describe the relationships that can be created between those tables in a relational database. Relations have three important properties a name, cardinality and degree. These are described as:
> Name: The first property of a relation is its name which is represented by the title or entity identifier.
> Cardinality: It refers to the number of rows in relation that defines the uniqueness of data value contained in a column.
> Degree: It refers to the number of column (attributes) in each tuple.
(iii) Domain: It is defined as the set of all unique values permitted for an attribute. For example; a domain of dates is the set of all possible valid dates, a domain of integer is all possible whole number, a domain of days of week is Monday, Tuesday Sunday. [4]
(f) Write the SQL query commands for (i) to (iv) based on following labels: [4]
| Book_id | Book_name | Author_name | Publisher | Price | Type | Quantity |
| C0001 | Fast Cook | Lata Kapoor | Oswaal | 355 | Cookery | 5 |
| F0001 | The Tears | William Hopkins | First Publ. | 650 | Fiction | 20 |
| T0001 | My First C++ | Brain \& Brooks | Oswaal | 350 | Text | 10 |
| T0002 | C++ Brain works | A.W. Rossaine | THH | 350 | Text | 15 |
| F0002 | Thunderbolts | Anna Roberts | First Publ. | 750 | Fiction | 50 |
(i) To display Name, Price of all books.
(ii) To display name of those authors whose book’s price is more than 700.
(iii) To display all records.
(iv) To display records for those books whose publisher is Oswaal.
Answer:
(i) SELECT Book_Name, Price FROM Book;
(ii) SELECT Author_Name FROM Book WHERE Price> 700;
(iii) SELECT * FROM Book;
(iv) SELECT * FROM Book WHERE
Publisher=”Oswaal”; [4]
Question 6.
(a) Out of the following, find the identifiers, which cannot be used for naming variable or functions in a Python Program :
_ Cost, Price *Qty, float, Switch, Address one, Delete, Number21, Do [2]
Answer:
(a) Price* Qty, float, Address one cannot be used for naming variable or functions in a Python Program. [2]
(b) Predict the output
x = 15
y = 10
z = 15
print (x = = y)
print (x > z)
print (z < y)
Answer:
Output
False
False
False [2]
(c) Write a program to calculate the factorial of a number.
Answer:
num = int (input (“Enter a number :”))
fact = 1
for i in range (1, num + 1) :
fact = fact * i
print (“The factorial of “, num, “is”, fact) [3]
(d) How are dictionaries different from lists?
Answer:
The dictionary is similar to lists in the sense that it is also a collection of data-items similar to lists. The only difference between lists and dictionaries are lists are sequential collections and dictionaries are non sequential collections. In lists, there is an order associated with the data items because they act as storage units for other objects or variables created. Dictionaries are different from lists and tuples because the group of objects they hold are not in any particular order, but rather each object has its own unique name, commonly known as a key. [3]
Question 7.
(a) What is sensor?
Answer:
(i) Sensors are very commonly used for monitoring and observing elements in real world applications. The evaluation of smart electronic sensors is constructing in a large way to the evolution of IoT. It will lead to creation of new sensor based intelligent systems.
(ii) A smart sensor is a device that takes input from the physical environment and uses built in computing resources to perform predefined functions upon detection of specific input and then process data before passing it on. [2]
(b) Explain the cloud services.
Answer:
Cloud computing can be separated into three general services as:
(i) Infrastructure as a Service (IaaS): It
contains the basic building blocks for cloud IT. It provides access to networking features, computers and data storage space.
(ii) Platform as a Service (PaaS): It removes the need for you to manage underlying infrastructure and allows you to focus on the deployment and management of your applications.
(iii) Software as a Service (SaaS): It provides you with a complete product that is run and managed by the service provider. In most cases, people referring to SaaS are referring to end user application. [2]
Case Based Questions (Attempt any 4)
Question 8.
Consider the following dictionary in Python.
Book={“Name”: “Information Technology”, “Price”: 560, “Author”: “Dr. D.S. Yadav”, “Pages”: 480, “Year”: 1998}
(i) print(Book[“Pages”]) displays:
(A) 480
(B) Invalid statement
(C) Pages:480
(D) None of these
Answer:
(A) 480
(ii) print(Book[“Dr. D.S. Yadav”]) displays:
(A) Author
(B) Error
(C) Author: Dr. D.S.Yadav
(D) None of these
Answer:
(B) Error
(iii) Length of dictionary Book is:
(A) 10
(B) 14
(C) 5
(D) None of these
Answer:
(C) 5
(iv) The statement Book[10] = “Edition” will:
(A) Generate error
(B) Add new element into dictionary as (10: ‘Edition’)
(C) Add new element into dictionary as (‘Edition’: 10)
(D) None of these
Answer:
(B) Add new element into dictionary as (10: ‘Edition’)
(v) The statement Book[“Price”] = 1050 will:
(A) Update the price of the book
(B) Add a new element into dictionary as (‘Price’: 1050)
(C) Generate error because Price is already present
(D) None of these
Answer:
(A) Update the price of the book