Students must start practicing the questions from CBSE Sample Papers for Class 11 Informatics Practices with Solutions Set 7 are designed as per the revised syllabus.
CBSE Sample Papers for Class 12 Informatics Practices Set 7 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) Converts the output in binary form to human readable form. [1]
(A) Input devices
(B) Output devices
(C) Storage device
(D) None of these
Answer:
(B) Output devices [1]
Explanation: An output device is any piece of computer hardware equipment which converts information into a human- perceptible form or, historically, into a physical machine-readable form for use with other non-computerized equipment. It can be text, graphics, tactile, audio, or video.
(ii) Which type of Programming does Python support? [1]
(A) object-oriented programming
(B) structured programming
(C) functional programming
(D) All of the above
Answer:
(D) All of the above [1]
Explanation: Python is an interpreted programming language, which supports object-oriented, structured, and functional programming.
(iii) Example(s) of DBMS is/are- [1]
(A) Oracle
(B) SQL
(C) MySQL
(D) All of these
Answer:
(D) All of these [1]
Explanation: DBMS examples include MySQL, PostogreSQL, SQL, ORACLE, RDBMS, etc.
(iv) A constraint written after all the column definitions are over in CREATE TABLE command is applicable to- [1]
(A) Last column
(B) First column
(C) Invalid syntax
(D) Complete table
Answer:
(D) Complete table [1]
Explanation: A column constraint is applicable only to a column whereas a table-constraint is applicable to multiple columns.
(v) Virtual Reality (VR) is a ______ dimensional, computer-generated situation that simulates the real world. [1]
(A) One
(B) Two
(C) Three
(D) N-dimensional
Answer:
(C) Three [1]
Explanation: Everything that we experience in our reality is perceived through our senses. From this came the idea that if we can present our senses with made-up or non-real information, our perception of reality would also alter in response to that Virtual Reality (VR) is a three-dimensional, computer-generated situation that simulates the real world.
Question 2.
(a) What do you mean by pen drive ? [1]
Answer:
Pen drive is a data storage device that consists of flash memory with a portable USB. [1]
(b) Differentiate between RAM and ROM. [2]
Answer:
| RAM | ROM |
| (i) RAM is volatile and is erased when the computer is switched off. | (i) ROM is non-volatile and generally cannot be written to. |
| (ii) RAM is used for both read and write. | (ii) ROM is used only for reading. |
(c) What are the advantages of using general purpose software ? [2]
Answer:
Advantages of using general purpose software:
(i) These are relatively cheap.
(ii) Easily available.
(iii) Thoroughly tested.
(iv) Easy to use [2]
(d) Explain operating system. [4]
OR
Explain in brief about the fifth generation computers. [4]
Answer:
Operating System (OS) is the core software component of computer system that manages the hardware and application software. The OS performs basic tasks such as controlling and allocating memory, prioritizing the processing of instructions, controlling input and output devices, networking, facilitating and managing files, translates the specific service programs and manages data needed to produce the output as desired by users. It activates all devices and make them ready to work.
The application programs do not access the hardware resources directly. Therefore, an operating system is required to use and access the hardware resources. OS provides a stable, consistent way for applications to deal with the hardware without having to known all the details of the hardware. This task is especially important if there is to be more than one of a particular type of computer using the operating system. [4]
OR
Fifth generation computers were developed in 1980’s and used the concept of Artificial Intelligence. Desktop, notebook or laptop, palmtop, server, mainframe and super computers are all belong to the fifth generation. Some of the characteristics of various fifth generation computers are given below:
- Desktop are based on IC’s.
- Notebook or laptop computer is same as desktop but can be carried around.
- Palmtop is mini version of laptop and has limited capabilities.
- Server is a powerful version of desktop that is used for various applications in a network.
- Mainframe is more powerful than server and has huge application handling and data processing capabilities.
- Supercomputers have multiprocessors to perform typical scientific applications requiring processing of trillions of information per second.
Question 3.
(a) In how many ways, you can work with Python? [1]
Answer:
You can work in Python with two ways
(i) Interactive Mode
(ii) Script Mode. 1
(b) What are Boolean numbers in Python? [1]
Answer:
0 and 1 are Boolean numbers in Python as internally they represent False and True respectively. [1]
(c) What is the error in the following code
a, b, c = 10 [1]
Answer:
Multiple assignment is not correct because the correct way is:
a = b= c = 10 [1]
(d) What are operators? [1]
Answer:
Operators are special symbols which perform some computation. Operators and operands form an expression. [1]
(e) Why does the expression 2 + 3*4 result in the value 14 and not the value 20? [2]
OR
Write a program to print negative, zero or positive according to whether variable x is less than zero, zero or greater than zero respectively. [2]
Answer:
Operator precedence rules make the expression to be interpreted as 2 + (3*4) hence the result is 14. [2]
OR
num = int (input (“Enter the number if num > 0 :
print (“Number is positive”) elif (num < 0) :
print (“Number is negative”) else :
print (“zero”) [2]
Commonly Made Error:
Some students do not use colon after conditional ‘ i statements.
Answering Tip:
Use colon after conditional statements as if, for, ! i while, else, etc.
(f) Write a Python program to take in two strings and display the larger string. [4]
Answer:
string1 = input (“Enter first string:”)
string2=input(“Enter second string:”)
a=0
b=0
for i in string1:
a=a+1
for j in string2:
b = b + 1
if (a<b):
print (“Larger string is:”)
print (string2)
elif(a==b):
print(“Both strings are equal.”)
else:
print(“Larger string is:”)
print(string1) [4]
Question 4.
(a) What do you mean by Data Abstraction in DBMS? [3]
Answer:
Data abstractions in DBMS refers to the hiding of unnecessary data from the end users, Database systems have complex data structures and relationships. These difficulties are masked so that users may readily access the data, and just the relevant section of the database is made accessible to them through data abstraction. [3]
(b) Consider the following table CLASS and predict the output of the following queries
| ROLL | NAME | ENG | COMPUTER |
| 1 | ANJEALI | 72 | 59 |
| 2 | RAM | 85 | 75 |
| 3 | JOY | 26 | 91 |
| 4 | YASH | 56 | 82 |
(i) SELECT ENG + COMPUTER AS ‘TOTAL’ FROM CLASS WHERE ROLL = 1;
Answer:
TOTAL
131
(ii) SELECT (ENG+ COMPUTER)/2 AS ‘AVG’ FROM CLASS WHERE ROLL =3;
Answer:
AVG 58.5
(iii) SELECT NAME FROM CLASS WHERE ENG=85; [3]
Answer:
NAME
RAM [3]
(c) What is cardinality, degree and domain? [3]
Answer:
A domain is a set of allowable values for one or more attributes. The degree of a relation is the number of attributes or columns it contains. The cardinality of a relation is the number of tuples or rows it contains. [3]
(d) What is alternative key give a suitable example? What is difference between candidate key and alternate key? [4]
Answer:
Difference between candidate key and alternate key: Alternate key is a key that can be work as a primary key. Basically, it is a candidate key that currently is not the primary key. Example: Admission No becomes Alternate Keys when we define Registration No. as Primary Key, in any table.
Candidate Key is a set of attributes that uniquely identify tuples in a table. Candidate Key is a super key with no repeated attributes. Alternate Key is a column or group of columns in a table that uniquely identify every row in that table. [4]
Question 5.
(a) Define the first property of a relation. [1]
OR
Can primary key contain NULL entry also? [1]
Answer:
The first property of a relation is its name which is represented by the title or entity identifier.[1]
OR
No [1]
(b) Write command to create table Hospital whose fields are [2]
| H_ID | int |
| Name | char |
| Department | varchar |
| Address | varchar |
| No_of_Staff | int |
| Fees | int |
Answer:
CREATE TABLE Teacher
(H_ID int Primary Key,
Name Char (20),
Department Varchar(20),
Address Varchar (30),
No_of_Staff int,
Fees int); [2]
(c) From table Hospital in Q. No. (5) (b), answer the following questions: [2]
(i) Identify the primary key
(ii) Identify the candidate key
Answer:
(i) H_ID
(ii) H_ID,Name 2
(d) Distinguish between cardinality and degree. [2]
Answer:
Cardinality refers to the number of rows (tuples) in a relation while degree refers to the number of columns (attributes) in each tuple. [2]
(e) What do you understand by Referential integrity? What are the conditions for it? [4]
Answer:
Referential integrity is a system of rules that a DBMS uses to ensure that relationships between records in related tables are valid and that users don’t accidentally delete or change related data. To set referential integrity ensures that,
(i) The matching field from the primary table is a primary key or has a unique indeed.
(ii) The related fields have the some data types,
(iii) Either both the tables belong to the some database or they must be of some DBMS format. The database must be open to set referential integrity. [4]
(f) Consider the table ABC given below, write commands in SQL for (i) to (iv):
| PID | Name | Gender | City | Pincode | Basic Salary |
| 1 | Geet | F | Udhamwara | 132141 | 50000 |
| 2 | Surinder | M | Kupwara Nagar | 193421 | 75000 |
| 3 | Peter | M | Bhawani | 434341 | 45000 |
| 4 | Thomas | M | Ahmed Nagar | 390021 | 50000 |
| 5 | Garima | F | New Delhi | 182141 | 35000 |
| 6 | Simi | F | Udhamwara | 110021 | 42000 |
(i) Display the Name, and City of People residing in Udhamwara city.
(ii) Display all records of table ABC.
(iii) Display the Name and city of all the females getting Basic Salary above 40000.
(iv) Display Name and Basic Salary of all the persons whose Name is garima. [4]
Answer:
(i) SELECT Name, City FROM ABC WHERE
City=”Udhamwara”;
(ii) SELECT * FROM ABC;
(iii) SELECT Name , City FROM ABC WHERE Gender =’F’ AND Basic Salary >40000;
(iv) SELECT Name Basic Salary FROM ABC
WHERE Name = “Garima”; [4]
Question 6.
(a) Predict the output of the following code
x = 3
y = 2
z =x + y-2 + 3 * 2
x = y + 2
Z = X + z
print (“Python Program”)
print (“Value of x : “, x)
print (“Value of y : “, y)
print (“Value of z : “, z) [2]
Answer:
Output
Python Program
Value of x : 4
Value of y : 2
Value of z : 13 [2]
(b) Find the output
pow1 = [2 ** x for x in range (12)]
print (pow1) [3]
Answer:
Output:
[1, 2,4,8,16, 32,64,128,256, 512,1024,2048] [3]
(c) What does not in operator do? [3]
Answer:
not in is a membership operator. It evaluates to True if it does not find a variable in a specified sequence. Otherwise it evaluates to False.
e.g.
>>> stu = {‘Name’ : ‘Washim’, ‘Age’ : 15}
> > > ‘Age’ not in stu
False [3]
(d) State when only first argument be evaluated and when both in following expressions,
if a = 12, b = 26, c = 23 and d =0.
(i) b > c and c > d
(ii) a< = bor c < = d
(iii) (b + c) > = a and not (c < a)
(iv) b < d and d < a [2]
Answer:
(i) both
(ii) first
(iii) first
(iv) first [2]
Question 7.
(a) Define the following terms:
(i) IaaS
(ii) PaaS. [2]
Answer:
(i) IaaS:
IaaS stands for Infrastructure as a Service that contains the basic building blocks for cloud IT. It provides access to networking features, computers and data storage space.
(ii) PaaS:
PaaS stands for Platform as a Service that removes the need for you to manage underlying infrastructure and allows you to focus on the deployment and management of your application. [2]
(b) What do you mean by virtual Reality? [2]
Answer:
Virtual Reality is a three dimensional, computer generated situation that simulates the real world. VR tries to stimulate as many senses as possible to make the user feel as if they are really there. Google’s Expedition is a great example of mobile VR in action, offering users the opportunity to explore imaginary world. [2]
Case Based Questions [Attempt any 4]
8. Lists are the container which store the heterogeneous elements of any type as integer, character, floating that store in square brackets [ ].
Consider the following list: [4]
L=[10,20, [3.4,6.7, 8.9], ‘apple’, ‘cat’, ‘duck’]
(i) To print the value 6.7, the python statement will be:
(A) L[2][l]
(B) L[2][—2]
(C) L[-4][1]
(D) All of the above
Answer:
(D) All of the above
(ii) The length of L is:
(A) 8
(B) 6
(C) 17
(D) None of these
Answer:
(B) 6
(iii) len(L[3]) will generate output:
(A) 5
(B) 6
(C) 3
(D) 4
Answer:
(A) 5
(iv) print(L[:2]) will generate value:
(A) [10]
(B) [10,20,3.4]
(C) [10, 20]
(D) Error
Answer:
(C) [10, 20]
(v) L.append [9,9,9] will generate output:
(A) Error
(B) Append a sublist [9,9,9] into L
(C) Append two elements 9 and 9.9
(D) None of these
Answer:
(D) None of these