Computer Science: CUET Mock Test - 4 - CUET MCQ

A Python variable is a reserved memory location to store values. In other words, a variable in a python program gives data to the computer for processing. Variables cannot, however, be named the same as keywords (as in case with "try" which is a python variable). Variables cannot contain any special character except "_". They cannot start with numbers and can only contain alphabets, numbers, and underscore (_)

A bus topology is a type of network topology in which all devices are connected to a single cable called a bus, not in ring topology. A star topology is a type of network topology in which all devices are connected to a central hub or switch not in a bus topology. Both are not correct.

Data manipulation languages are divided into two types, procedural programming and declarative programming.

In MAN, different LANs are connected through a local telephone exchange. Some of the widely used protocols for MAN are RS-232, X.25, Frame Relay, Asynchronous Transfer Mode (ATM), ISDN (Integrated Services Digital Network), OC·3 lines (1.55 Mbps), ADSL (Asymmetrical Digital Subscriber Line). These protocols are quite different from those used for LANs.

The rewind() function sets the file position to the beginning of the file for the stream pointed to by stream. It also clears the error and end-of-file indicators for stream.

• Client-server architecture is an architecture in which devices are connected to a central server, which provides services to clients. Clients request services from the server, which then provides a response.
• Peer-to-peer architecture is an architecture in which devices communicate directly with each other without a central server. Each device can act as both a client and a server.
• Service-oriented architecture (SOA) is an architecture in which services are exposed as independent components that can be accessed over a network. Services can be combined to create more complex applications.
• Cloud architecture is an architecture in which resources are provisioned dynamically and accessed over a network. It allows users to access resources such as storage and computing power on-demand.

In this program, getc() function within the while loop will read the characters from TCY.c one by one and display on the screen through the variable Tch.

The tell() method can be used to get the position of File Handle. It returns the current position of the file object. This method takes no parameters and returns an integer value.

The append() method adds an item to the end of the list.

The following program, print((1,2) + (3,4)) gives:
For the given program, we have two tuples, and we are printing the concatenation of these tuples.
i.e print((1, 2) + (3, 4))
A collection of Python objects separated by comma is called a Tuple.
In this, we are using the concatenation operator +, to join the two tuples.
So, (1,2,3,4) is the answer.

Following is the various Applications of Stack in Data Structure:

• Evaluation of Arithmetic Expressions
• Backtracking
• Delimiter Checking
• Reverse a Data
• Processing Function Calls

Non-Procedural DML or High level DML requires a user to specify what data are needed without specifying how to get those data.

Insert is a widely-used command in the Structured Query Language (SQL) data manipulation language (DML) used by SQL Server and Oracle relational databases. The insert command is used for inserting one or more rows into a database table with specified table column values.

White hat hackers are security professionals who follow ethical and legal behavior. Their objective is to help improve security.

Communication bandwidth that has the highest capacity and is used by microwave, cable and fibre optic lines is known as broadband.

The append() method in Python adds a single item to the existing list.

The len function returns the length of the stack, i.e. number of items in stack. The value 0 itself means that the stack is empty.

This will call the function pop() by passing the stack 'Country' as an argument. The function pop is already defined in the given code as: def pop (Country):.

The '2' in the given 'for' statement is the step value which specifies the difference between two consecutive values in the range. Here, the step value is used to refer to the index position of the items in stack. To insert the alternate element, the step value will be taken as 2.

pop() removes the last value from the stack and returns it.

The correct answer is option C.
Concept:
To open a file in Python:
we use the open() function. The syntax of open() is as follows:
file_object= open(file_name, access_mode)
The access_mode is an optional argument that represents the mode in which the file has to be accessed by the program. It is also referred to as processing mode.
Different File open modes:

• <wb+> or <+wb> Opens the file in read, write, and binary mode. If the file already exists, the contents will be overwritten. If the file doesn’t exist, then a new file will be created.
• <r> Opens the file in read-only mode.
• <rb> Opens the file in binary and read-only mode.
• <w> Opens the file in write mode. If the file already exists, all the contents will be overwritten. If the file doesn’t exist, then a new file will be created.
• <a> Opens the file in append mode. If the file doesn’t exist, then a new file will be created.​

Hence the correct answer is<wb+> or <+wb>.

Selection sort works in the algorithm like we have to pick the smallest element from the unsorted array/list and move that to the beginning of the list. This process can be described  as 1 Swap.
Applying Selection sort on the given list - 
Pass 1 = {12}   {23,54,44,18,22,14}  - 1 swap 
Pass 2 = {12,14}  {54,44,18,22,23}  - 2nd swap
Pass 3 = {12,14,18}   {44,54,22,23} - 3rd  swap
Pass 4 = {12,14,18,22}  {44,54,23} - 4th  swap 
Pass 5 = {12,14,18,22,23}   {44,54}  - 5th swap 
Pass 6 = {12,14,18,22,23,44}  {54}  - 6th swap 
For the last element we do not need any swap, So, in total 6 swap required to sort the list. ( option 1) 
Formula - For a n element list , Selection Sort needs (n-1) number of swap. , where n is number of element in a list.

Queue is a data structure which follows FIFO pattern ( first in first out) means the element which inserted first should come out first. 
In queue , enqueue means inserting an element and dequeue means deleting an element from the queue. 
Remember , delete should happen from the front and insert should happen from back ( rear ) side.
So, To implement the enqueue operation , we need to first check the queue is full or not, for that we use isfull() function , which returns a binary value - either true or false .
To implement dequeue operation we need to first check if element present in the queue or not, for that we need isempty() function , if the function returns false that means queue have at least 1 element and we can delete that. 
peek() function used to return the front element of the queue , as deletion happens from the front , so, we need peek operation to find out the front element.
So, option 3 will be the correct answer .
Why option 1 and 2 got eliminated - 
we need 3 operation ( isempty,isfull,peek ) combine for the operation , and the options does not satisfy that . 
why option 4 got eliminated - 
insertrear() function used to insert an element in the rear position , but here , in this question , we do not require that. 

The correct answer is option C.
Concept:
Statement 1: dump() method is used to write the objects in a binary file. 
True, the dump() method is used to convert (pickling) Python objects for writing data in a binary file. The file in which data are to be dumped needs to be opened in binary write mode (wb).
Syntax of dump() is as follows:
dump(data_object, file_object)
Statement 2: load() method is used to read data from a binary file.
True, The load() method is used to load (unpickling) data from a binary file. The file to be loaded is opened in binary read (rb) mode. Syntax of load() is as follows:
Store_object = load(file_object)
Hence the correct answer is Both statement 1 and statement 2 are true.

The POP() method is generally called when we want to remove an element from the queue, So, before that, we have to check whether the queue has an element or not. else, we cannot remove an element from an empty queue.
So, to check queue contains an element or not, we use Isempty() function, if it returns true that means the queue is empty and we cannot apply pop(). 
if it returns false that means the queue has some element and we can use the pop() function. Remember empty() always returns binary value - "either true or false"
Why option 1 got eliminated - 
Len() used to check the length of a list in python, we cannot apply it in the queue. 
Why option 2 got eliminated - 
is full() is used to check queue is full or not. This is the reverse case of the question asked. it is used when we want to insert an element
why option 3 got eliminated - 
the str() function is used to convert any data type to a string data type in python. it has no relation to queue deletion. 

The correct answer is option A.
Concept:
The given python code is,
try:
    sum=5/2;
except ZeroDivisionError:    
    print("Hello India")    
else:    
    print("Hello world")    
try:
    sum=5/2;
except ZeroDivisionError:    
    print("Hello India")    
else:    
    print("Hello world")  

Explanation:
ZeroDivisionError:
It is raised when the denominator in a division operation is zero.
try:
    sum=5/2;
except ZeroDivisionError:    
    print("Hello India")    
else:    
    print("Hello world")    

The above executes and it can not raise the exception and prints the Hello world as output.

try:
    sum=5/2;
except ZeroDivisionError:    
    print("Hello India")    
else:    
    print("Hello world")  
The above executes and it can raise the exception and print the Hello India as output.
Hence the correct answer is  
Hello world

Hello India

The correct answer is option 4.

Concept:
To open a file in Python:
we use the open() function. The syntax of open() is as follows:
file_object= open(file_name, access_mode)
The access_mode is an optional argument that represents the mode in which the file has to be accessed by the program. It is also referred to as processing mode. 

Different File open modes:

•  <r> Opens the file in read-only mode.
• <rb> Opens the file in binary and read-only mode.
• <w> Opens the file in write mode. If the file already exists, all the contents will be overwritten. If the file doesn’t exist, then a new file will be created.
• <a> Opens the file in append mode. If the file doesn’t exist, then a new file will be created.​

Hence the correct answer is <a>.

The correct answer is option A.
Concept:
The given python code is,
try:    
    fileptr = open("file.txt","r")    
except IOError:    
    print("File not found")    
else:    
    print("The file opened successfully")    
    fileptr.close()    

Explanation:
It is an error raised when an input/output operation fails, such as the print statement or the open() function when trying to open a file that does not exist. It is also raised for operating system-related errors.
The file pointer fileptr is open the file.txt in reading mode and that file is not found so try clause raise the error. That resolve in except block and prints the statement like File not found as output.
Hence the correct answer is File not found.

Queue is a data structure which uses FIFO mode of operation ( first in first out), means the element inserted first should be removed first from the queue.
peek() method of the queue returns the front or first element of the queue.but it does not delete that element , it just return that element. 
why option 2 got eliminated - 
IS FULL() method is used to check the queue is full or not at certain point of time, We generally check this if we want to insert a element in the queue.else it will throw "queue out of memory " error.
Why option 3 got eliminated - 
seek() is used to change the option of file handle in python , to move a file to some specific place , we use seek function. it is not related with queue. 
Why option 4 got eliminated -
IS EMPTY() method is used to check queue is empty or not at certain point of time. we generally use this if we want to delete a element from queue.Else it will give " no element in queue " error . 

Insertion sort works by the algorithm like to compare every element with the element in its left side , if they are smaller , skip , else swap the element. 

Applying insertion sort in list 1 :
L1- {2,4,6,8,10} 
If the list is already sorted , then insertion sort do (n-1) number of comparison . 
So, in total we need 4 comparison for this List . 

L2 - {10.4,6,8,10}
Pass 1 - compare 10 and 4 , swap the position - {4,10,6,8,10}  - 1 comparison 
Pass 2 - compare 10 and 6 , swap them , again compare 6 and 4( no swapping required - {4,6,10,8,10} - 2 comparison 
Pass 3 - Compare 8 and 10 , swap them , again compare 8 with 6 and 4( no swap as they are already sorted ) - {4,6,8,10,10}-3 comparison 
Pass 4 - compare 10 with 10 , as they are same element , so, no swapping required ,and here , list got sorted - {4,6,8,10,10} - 1 comparison 
So, in total we need 7 comparison to sort list 2 . 

Question asks about minimum number of comparison , so, Option A will be the answer.