Computer Science (Python) Set 4 2022-2023 Commerce (English Medium) Class 12 Question Paper Solution

"Identifiers are names used to identify a variable or function in a program". 

True

False

Which of the following is a valid keyword in Python?

false

return

non_local

none

Given the following Tuple.

Tup = (10, 20, 30, 50)

Which of the following statements will result in an error?

print(Tup [0])

Tup.insert (2, 3)

print(Tup[1:2])

print(len(Tup))

Consider the given expression:

5<10 and 12>7 or not 7>4

Which of the following will be the correct output if the given expression is evaluated?

TRUE

FALSE

NONE

NULL

Select the correct output of the code:

S="Amrit Mahotsav @ 75"
A=S.partition (" ")
print(a)

(‘Amrit Mahotsav’, ‘@’, ‘75’)

[‘Amrit’, ‘Mahotsav’, ‘@’, ‘75’]

(‘Amrit’, ‘Mahotsav @ 75’)

(‘Amrit’, “, ‘Mahotsav @ 75’)

Which of the following mode keeps the file offset position at the end of the file?

r+

r

w

a

______ function is used to arrange the elements of a list in ascending order.

sort()

arrange()

ascending()

asort()

Which of the following operators will return either True or False?

+=

!=

=

*=

Which of the following statement(s) would give an error after executing the following code?

Stud = {"Murugan": 100, "Mithu": 95} # Statement 1
print (Stud [95])                    # Statement 2 
Stud ["Murugan"]=99                  # Statement 3
print (Stud.pop())                   # Statement 4 
print (Stud)                         # Statement 5 

Statement 2

Statement 3

Statement 4

Statements 2 and 4

The number of tuples in a relation is called ______.

Attribute

Tuple

Cardinality

Degree

Domain

The syntax of seek() is:
file_object.seek(offset[,reference_point])

What is the default value of reference_point?

0

1

2

3

______ clause is used with a SELECT statement to display data in a sorted form with respect to a specified column.

WHERE

ORDER BY

HAVING

DISTINCT

______ is used for point-to-point communication or unicast communication such as radar and satellite. 

INFRARED WAVES

BLUETOOTH

MICROWAVES

RADIOWAVES

What will the following expression be evaluated for in Python?

print (4 + 3 * 5/3 − 5 % 2)

8.5

8.0

10.2

10.0

Which function returns the sum of all elements of a list?

count()

sum()

total()

add()

fetchall() method fetches all rows in a result set and returns a:

Tuple of lists

List of tuples

List of strings

Tuple of strings

Assertion (A): To use a function from a particular module, we need to import the module.

Reason (R): Import statement can be written anywhere in the program, before using a function from that module.

Both (A) and (R) are true and (R) is the correct explanation for (A).

Both (A) and (R) are true and (R) is not the correct explanation for (A).

(A) is true, but (R) is false.

(A) is false, but (R) is true.

Assertion (A): A stack is a LIFO structure.

Reason (R): Any new element pushed into the stack always gets positioned at the index after the last existing element in the stack.

Both (A) and (R) are true and (R) is the correct explanation for (A).

Both (A) and (R) are true and (R) is not the correct explanation for (A).

(A) is true, but (R) is false.

(A) is false, but (R) is true.

Atharva is a Python programmer working on a program to find and return the maximum value from the list. The code written below has syntactical errors. Rewrite the correct code and underline the corrections made.

def max_num (L):
        max=L(O)
        for a in L:
                if a > max
                 max=a
        return max

Differentiate between wired and wireless transmission.

Differentiate Domain name and URL.

Given is a Python list declaration:

Listofnames = ["Aman", "Ankit", "Ashish", "Rajan", "Rajat"]

Write the output of:

print (Listofnames [−1:−4:−1])

Consider the following tuple declaration:

tup1 = ( 10, 20, 30, (10, 20, 30), 40)

Write the output of:

print(tupl.index(20))

Explain the concept of “Alternate Key” in a Relational Database Management System with an appropriate example.

Write the full form of the following:

HTML

Write the full form of the following protocol:

TCP

What is the need for Protocols?

Write the output of the code given below:

def short_sub (1st, n):
for i in range (0, n):
      if len (1st) > 4:
          lst [i] = lst [i] + lst [i]
      else:
          lst [i] = lst [i]
subject = ['CS', 'HINDI', 'PHYSICS', 'CHEMISTRY', 'MATHS'] 
short_sub (subject, 5)
print (subject)

Write the output of the code given below:

a = 30
def call (x):
          global a
          if a%2==0:
             x+=a
          else:
             x−=a
          return x 
x=20
print (call (35), end="#") 
print (call (40), end="@")

Differentiate between CHAR and VARCHAR data types in SQL with appropriate examples.

Name any two DDL commands.

Name any two DML commands.

Consider the following tables – LOAN and BORROWER:

Table: LOAN

Table: BORROWER

How many rows and columns will be there in the natural join of these two tables?

Write the output of the queries (i) to (iv) based on the table, WORKER given below:

TABLE: WORKER

1. SELECT F_NAME, CITY FROM WORKER ORDER BY STATE DESC;
2. SELECT DISTINCT (CITY) FROM WORKER;
3. SELECT F_NAME, STATE FROM WORKER WHERE L_NAME LIKE '_HA%';
4. SELECT CITY, COUNT(*) FROM WORKER GROUP BY CITY;

Write the definition of a Python function named LongLines() which reads the contents of a text file named 'LINES.TXT' and displays those lines from the file which have at least 10 words in it. For example, if the content of 'LINES.TXT' is as follows: 

Once upon a time, there was a woodcutter
He lived in a little house in a beautiful, green wood.
One day, he was merrily chopping some wood.
He saw a little girl skipping through the woods, whistling happily.
The girl was followed by a big gray wolf. 

Then the function should display output as:

He lived in a little house in a beautiful, green wood.
He saw a little girl skipping through the woods, whistling happily.

Write a function count_Dwords() in Python to count the words ending with a digit in a text file "Details.txt".

Example:
If the file content is as follows:
On seat2 V1P1 will sit and
On seat1 VVIP2 will be sitting
The output will be:
The number of words ending with a digit is 4

Write the outputs of the SQL queries (i) to (iv) based on the relations COMPUTER and SALES given below:

1. SELECT MIN(PRICE), MAX(PRICE) FROM COMPUTER;
2. SELECT COMPANY, COUNT(*) FROM COMPUTER GROUP BY COMPANY HAVING COUNT(COMPANY) > 1;
3. SELECT PROD_NAME, QTY_SOLD FROM COMPUTER C, SALES S WHERE C.PROD_ID=S.PROD_ID AND TYPE = 'INPUT';
4. SELECT PROD_NAME, COMPANY, QUARTER FROM COMPUTER C, SALES S WHERE C.PROD_ID=S.PROD_ID;

Write the command to view all databases.

Write a function EOReplace() in Python, which accepts a list L of numbers. Thereafter, it increments all even numbers by 1 and decrements all odd numbers by 1.

Example:

If Sample Input data of the list is:

L = [10, 20, 30, 40, 35, 55]

Output will be:

L = [11, 21, 31, 41, 34, 54]

A list contains the following records of customers.

[Customer_name, Room Type]

Write the following user-defined functions to perform given operations on the stack named 'Hotel':

1. Push_Cust() - Push customers names of those customers who are staying in the 'Delux' Room Type.
2. Pop_Cust() - Pop the names of customers from the stack and display them. Also, display "Underflow" when there are no customers in the stack.

For example:
If the lists with customer details are as follows:

["Siddarth", "Delux"]
["Rahul", "Standard"]
["Jerry", "Delux"]

The stack should contain

Jerry
Siddharth 

The output should be:

Jerry
Siddharth 
Underflow

Write a function in Python, Push (Vehicle) where, Vehicle is a dictionary containing details of vehicles – {Car_Name: Maker}. The function should push the name of car manufactured by 'TATA' (including all the possible cases like Tata, TaTa, etc.) to the stack.

For example:
If the dictionary contains the following data:

Vehicle=["Santro":"Hyundai","Nexon":"TATA","Safari":"Tata"]

The stack should contain

Safari
Nexon

Quickdev, an IT based firm, located in Delhi is planning to set up network for its four branches within a city with its Marketing department in Kanpur. As a network professional, give solution to the questions, after going through the branches locations and other details which are given below: 

Distance between various branches is a follows:

Number of computers in each of the branches:

1. Suggest the most suitable place to install the server for the Delhi branch with a suitable reason.
2. Suggest an ideal layout for connecting all these branches within Delhi.
3. Which device will you suggest, that should be placed in each of these branches to efficiently connect all the computers within these branches?
4. Delhi firm is planning to connect to its Marketing department in Kanpur which is approximately 300 km away. Which type of network out of LAN, WAN, or MAN will be formed? Justify your answer.
5. Suggest a protocol that shall be needed to provide help for transferring of files between Delhi and Kanpur branch.

What possible output(s) are expected to be displayed on the screen at the time of execution of the following program:

import random
M=[5, 10, 15, 20, 25, 30]
for i in range(1, 3):
first=random.randint(2, 5)-1
sec=random.randint(3, 6)-2
third=random.randint(1, 4)
print(M[first],M[sec],M[third],sep="#") 

10#25#15
20#25#25

5#25#20
25#20#15

30#20#20
20#25#25

10#15#25#
15#20#10#

The code given below deletes the record from the table employee, which contains the following record structure:

E_code - String
E_name - String
Sal - Integer
City - String

Note the following to establish connectivity between Python and MySQL:

• Username is root
• Password is root
• The table exists in a MySQL database named emp.
• The details (E_code, E_name, Sal, City) are the attributes of the table.

Write the following statements to complete the code:

Statement 1 – to import the desired library.

Statement 2 – to execute the command that deletes the record with E_code as 'E101'.

Statement 3 – to delete the record permanently from the database. ____________

import ____________ as mysql #Statement1
def delete():
      mydb=mysql.connect(host="localhost",use r="root", 
      passwd="root",database="emp")

mycursor=mydb.cursor()
____________ #Statement 2
____________ #Statement 3
print ("Record deleted") 

Predict the output of the code given below: 

def makenew(mystr):
     newstr.=.""
     count=0
     for i in mystr:
        if count%2 ! = 0:
           newstr=newstr+str(count)
        else:
           if i.lower():
      newstr = newstr + i.upper ()
           else:
               newstr = newstr + i
       count+=1
    Print(newstr)
makenew("No@1") 

The code given below reads the following records from the table employee and displays only those records that have employees coming from the city 'Delhi':

E_code - String
E_name - String
Sal - Integer
City - String

Note the following to establish connectivity between Python and MySQL:

• Username is root
• Password is root
• The table exists in a MySQL database named emp.
• The details (E_code,E_name,Sal,City) are the attributes of the table.

Write the following statements to complete the code:

Statement 1 - to import the desired library.

Statement 2 - to execute the query that fetches records of the employees/coming from the city ‘Delhi’.

Statement 3 - to read the complete data of the query (rows whose city is Delhi) into the object named details, from the table employee in the database.

import ____________ as mysql  #Statement 1
def display():
   mydb=mysql.connect(host="localhost",user="root"
   passwd="root", database=" emp")
   mycursor=mydb.cursor()
   ____________ #Statement 2
   details = ____________ # Statement 3
   for i in details:
       print (i)

Write one difference between CSV and text files.

Write a program in Python that defines and calls the following use of defined functions:

1. COURIER_ADD(): It takes the values from the user and adds the details to a CSV file 'courier.csv’. Each record consists of a list with field elements as cid, s_name, Source, destination to store Courier ID, Sender name, Source, and destination address, respectively.
2. COURIER SEARCH(): Takes the destination as the input and displays all the courier records going to that destination. 

Why it is important to close a file before exiting?

Write a program in Python that defines and calls the following user-defined functions:

1. Add_Book(): Takes the details of the books and adds them to a CSV file ‘Book. csv'. Each record consists of a list with field elements such as book_ID, B_name and pub to store book ID, book name and publisher, respectively.
2. Search_Book(): Takes publisher name as input and counts and displays the number of books published by them. 

The school has asked their estate manager Mr Rahul to maintain the data of all the labs in a table LAB. Rahul has created a table and entered data from 5 labs.

Based on the data given above answer the following questions:

(i) Identify the columns which can be considered as Candidate keys.

(ii) Write the degree and cardinality of the table.

(iii) Write the statements to:

      (a) Insert a new row with appropriate data.

      (b) Increase the capacity of all the labs by 10 students which are on
           the 'I' Floor.

                                     OR

(iii) Write the statements to:

        (a) Add a constraints PRIMARY KEY to the column LABNO in the table.

        (b) Delete the table LAB.

Shreyas is a programmer, who has recently been given a task to write a user-defined function named write_bin () to create a binary file called Cust_file.dat containing customer information – customer number (c_no), name (c_name), quantity (qty), price (price) and amount (amt) of each customer. 

The function accepts customer number, name, quantity and price. Thereafter, it displays the message 'Quantity less than 10.....Cannot SAVE', if the quantity entered is less than 10. Otherwise, the function calculates the amount as price*quantity and then writes the record in the form of a list into the binary file. 

import pickle
def write_bin ():
bin_file = ____________ # Statement 1
while True:
c_no = int (input (“enter customer name”))
c_name = input (“enter customer name”)
qty = int (input ("enter qty"))
price = int (input ("enter price”))
if ________ # Statement2
print (“Quantity less than 10.. Cannot SAVE")
else:
amt = price * gty
c_detail = [c_no, c_name, qty, price, amt]
__________ # Statement 3
ans = input (" Do you wish to enter more records y/n”) if ans. lower () == 'n’:
          __________ # Statement 4
    ____________ # Statement 5
____________#Statement 6

(i) Write the correct statement to open a file 'Cust_file.dat’ for writing the data of the customer.

(ii) Which statement should Shreyas fill in statement 2 to check whether the quantity is less than 10?

(iii) Which statement should Shreyas fill in Statement 3 to write data to the binary file and in Statement 4 to stop further processing if the user does not wish to enter more records?
                                      OR
(iii) What should Shreyas fill in Statement 5 to close the binary file named Cust_file.dat and in Statement 6 to call a function to write data in the binary file?