MBOSE Class 12 Question Paper 2021 for Computer Science

Total No. of Printed Pages—8
HS/XII/A.Sc.Com/CSc/NC/21

2021

COMPUTER SCIENCE

( New Course )

( Theory )

Full Marks : 70

Time : 3 hours

The figures in the margin indicate full marks for the questions

General Instructions :

(i) Write all the answers in the Answer Script.

(ii) Attempt multiple choice questions and very short
answer-type questions serially.

(iii) Attempt all parts of a question together at one place.

1. Choose the correct option for the following : 1×6=6
(a) What is the output of this code?
>>> int (“3” + “4”)

(i) “7”

(ii) “34”

(iii) 34

(iv) 7

/116 [ P.T.O.

( 2 )

(b) A variable defined inside a function referred to as
(i) a static variable
(ii) a global variable
(iii) a local variable
(iv) an automatic variable

(c) Which function is used to read all the characters?
(i) read ( )
(ii) read characters ( )
(iii) read all ( )
(iv) read char ( )

(d) The terms Push and Pop are related to
(i) queue
(ii) stack
(iii) Both (i) and (ii)
(iv) None of the above

(e) A relational database consists of a collection of
(i) tables
(ii) fields
(iii) records
(iv) keys

(f) Which of the following SQL statements is incorrect?
(i) SELECT * FROM Employee WHERE
emp_id = 1000;
(ii) SELECT emp_id FROM Employee WHERE
emp_id = 1000;
(iii) SELECT emp_id FROM Employee WHERE
emp_id > 1000;
(iv) SELECT * FROM Employee WHERE emp_id is
1000;

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( 3 )

2. Answer the following questions in not more than 2 (two)
or 3 (three) sentences : 1×6=6
(a) What is string slice?
(b) What is scope?
(c) How is file open ( ) function different from close ( )
function?
(d) What is Python module?
(e) What is primary key?
(f) What is SQL join?

3. Answer the following questions : 2×6=12
(a) What are pickling and unplicking processes in the
context of binary file?
(b) What is the significance of having functions in a
program?
(c) What are the advantages of saving data in binary
form?
(d) Compare positional arguments with keyword
arguments.
(e) What are docstrings? What is their significance?
(f) Write the expressions to generate the random integers
between 20 to 50 using function random ( ).

4. Answer the following questions : 2×2=4
(a) What is bandwidth? How is it measured?
(b) Differentiate between Hub and Switch.
Or
Differentiate between a web browser and a web
server.

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( 4 )

5. Answer the following questions : 2×3=6

(a) What is the difference between WHERE clause and
HAVING clause of SQL SELECT statement?

(b) Explain, with example, the following aggregate
functions :
(i) Sum ( )
(ii) Max ( )

(c) Sweety is using a table ‘STUDENT’. It has the
following columns (fields) :
Admno, Name, Agg, Stream
[column Agg contains Aggregate marks]
She wants to display the highest Aggregate marks
obtained in each stream. She wrote the following
command :
SELECT Stream, MAX (Agg) FROM STUDENT;
But she did not get the desired result. Rewrite the
above query with necessary changes to help her get
the desired result.

6. Answer the following questions : 3×4=12
(a) Write a Python program to test a year is a leap year
or not.
Or
Write a Python program to input temperature in
Fahrenheit and convert it to Celsius. [C = (F – 32)*1·8]

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( 5 )

(b) Trace the flow of execution for the following program
by writing the integer given against each line in order.
1 def power (b, p) :
2 r = b**p
3 return r
4
5 def cal_square (a) :
6 a = power (a, 2)
7 return a
8
9 n=5
10 result = cal_square (n)
11 print (result)

(c) Give postfix form of the following infix expression :
A * (B + (C + D) * (E + F)/G) * H
Or
How can you return multiple values from a function?
Explain with the help of an example.

(d) Write a Python program to display the number of
lines present in a data file.
Or
Write the different types of Files Access Modes with
their usage.

7. Answer the following questions : 3×2=6
(a) Briefly explain the types of network on the basis of
geographical spread.
Or
Briefly explain the different network topologies.

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( 6 )

(b) What is virus? Mention the three types of viruses.
How can you prevent them?
Or
Write short notes on the following :
(i) HTTP
(ii) FTP

8. Answer the following questions : 3×2=6
(a) What is the significance of GROUP BY clause in a
SQL Query? Write a query to display the number of
employees with same job from the ‘EMP’ table.
(b) Consider the following tables Orders, OrderItems
and Product. Write a query to list all orders with
product names, quantities and prices arranged
orderId wise :

Or
What is the use of ORDER BY clause? Write a query
that sorts the data of a table ‘STUDENT’ on the basis
of Project-Group (in ascending order), Section (in
descending order), Marks (in descending order).

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( 7 )

9. Answer the following questions : 4×2=8
(a) What is the procedure to create own library/package
in Python?
Or
Write a function that takes amount in dollars and
convert to rupee. Create the function in both void
and non-void forms.
(b) Write a program to get item details (code, description
and price) for multiple items from the user and
create a CSV file by writing all the items details in
one go.
Or
Convert the following infix expression into postfix
expression :
(A + B) * C + (D/E * * F) – G

10. Write a Python code to connect to MySQL database
namely ‘SCHOOL’ and then fetches all those records
from table ‘STUDENT’ where marks >70. 4
Or
Given the following table :
Table : STUDENT

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( 8 )

Give the output of following SQL statements :

(a) SELECT MIN (AvgMark) FROM STUDENT WHERE
AvgMark < 75;

(b) SELECT SUM(Stipend) FROM STUDENT WHERE
Grade = ‘B’;

(c) SELECT Avg(Stipend) FROM STUDENT WHERE
Class = ‘12A’;

(d) SELECT COUNT(DISTINCT Stream) FROM
STUDENT;

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