Computer Science: CUET Mock Test - 7 - CUET MCQ

The Programming language Python is named after a popular BBC comedy show "Monty Python's Flying Circus".

The correct answer is AdmNo

Key Points

• The primary key in a database is a specific choice of attribute(s) which uniquely identifies each row in a table.
• For the given table student, the attribute that satisfies this requirement is AdmNo.
• Each student has a unique AdmNo, making it the best choice for a primary key in this context.
• Therefore, the correct answer is: AdmNo

The correct answer is Degree 7, Cardinality = 5

Key PointsThe degree of the table is 7, and the cardinality is 5.

• Degree refers to the number of columns (attributes) in a table. In this case, the table has 7 attributes.
• Cardinality refers to the number of rows (tuples) in a table. The table has 5 rows of data.

So, the correct answer is option 1: Degree 7, Cardinality = 5.

The correct answer is c#U#e#T#$#3#1#3#3#

Key Points

• s = "CuEt #2022": This line creates a string variable s and assigns the value "CuEt #2022" to it.
• f = open("new.Txt", "w+"): This line opens a new file named "new.Txt" in write-plus mode ("w+"). This mode allows both writing and reading to the file.
• f.write(s): This line writes the content of the string s (which is "CuEt #2022") to the opened file.
• f.seek(0): This line moves the file pointer to the beginning of the file. This is necessary because after writing, the pointer is at the end of the file.
• c = f.read(9): This line reads the first 9 characters from the file and stores them in the variable c. Since the string we wrote is less than 9 characters, it will only read those characters.
• Looping through c: The code then iterates through each character in the variable c using a loop.
• if i.isupper(): If the character is uppercase, it converts it to lowercase and prints it followed by a "#" (hash symbol).
• elif i.islower(): If the character is lowercase, it converts it to uppercase and prints it followed by a "#" (hash symbol).
• elif int(i).isdigit(): If the character is a digit, it converts it to an integer, adds 1 to it, converts it back to a string, and prints it followed by a "#" (hash symbol).
• else: If the character is none of the above (e.g., a special character), it prints "$" followed by a "#" (hash symbol).
• f.close(): Finally, the code closes the opened file.

Here's how the loop works for each character:

• 'C' (uppercase): Converted to lowercase 'c' and printed as "c#".
• 'u' (lowercase): Converted to uppercase 'U' and printed as "U#".
• 'E' (uppercase): Converted to lowercase 'e' and printed as "e#".
• 't' (lowercase): Converted to uppercase 'T' and printed as "T#".
• ' ' (space): Not an uppercase, lowercase, or digit, so printed as "$#". - **'#' (hash)**: Not an uppercase, lowercase, or digit, so printed as "$#".
• '2' (digit): Converted to int, incremented by 1, converted back to string ('3'), and printed as "3#".
• '0' (digit): Converted to int, incremented by 1, converted back to string ('1'), and printed as "1#".
• '2' (digit): Converted to int, incremented by 1, converted back to string ('3'), and printed as "3#".
• '2' (digit): Converted to int, incremented by 1, converted back to string ('3'), and printed as "3#".

As you can see, the output follows the logic of converting case, incrementing digits, and replacing special characters with "$".

The correct answer is TableA - TableB

Key Points

• TableA X TableB: This is the Cartesian product operation, which combines each row in TableA with each row in TableB. It results in a table with many more rows than either TableA or TableB, depending on their row counts. This operation does not match the provided Output.
• TableA ∪ TableB: This is the union operation, which combines all unique rows from both TableA and TableB. Duplicates are typically removed in a union operation, and the result will include rows unique to both tables and rows common to both tables but listed only once. The Output table listed does not match a union of TableA and TableB, as it does not include all unique entries from both tables.
• TableA - TableB: This is the difference operation, which returns rows that are in TableA but not in TableB. It essentially removes rows from TableA that have exact matches in TableB based on the columns specified. The Output table matches this description, as it shows rows from TableA that are not found in TableB.
• TableA ∩ TableB: This is the intersection operation, which returns rows that are common to both TableA and TableB. It essentially finds rows with the exact match across all columns specified in both tables. The Output table does not match an intersection of TableA and TableB because it excludes rows that are actually common to both tables (e.g., the rows for "Mahira" and "Sanjay").

Based on this analysis, the operation applied to obtain the given output is: TableA - TableB

The correct answer is 2

Key Points

• f=open('pledge.txt', 'r') (Statement 1): This line opens the file named 'pledge.txt' in read mode. If the file doesn't exist, it will cause an error.
• line = f.readlines() (Statement 2): This line reads all the lines from the opened file and stores them in a list variable named line. Since the file contains two lines, this list will have two elements.
• print(len(line)) (Statement 3): This line calculates the length of the list line, which represents the number of lines in the file. As the list has two elements (one for each line), the output of this statement will be 2.
• f.close() (Statement 4): This line closes the opened file, which is good practice to release resources.

Therefore, statement 3 (print(len(line))) will correctly print the number of lines in the file, which is 2.

The correct answer is Only 2 is correct.

Key Points

1. The first statement is incorrect. In a stack, the operation to remove an item is called "pop," not "enqueue." "Enqueue" is the term used in a queue for adding an item, and "dequeue" is correctly stated as the term for removing an item from a queue. Therefore, the description of the stack operation in this statement is incorrect.
2. The second statement is accurate. A queue indeed operates on the FIFO (First In, First Out) principle. This characteristic means that items are added to one end of the queue (rear end) and removed from the other end (front end), maintaining the order in which elements were added.
3. The third statement is incorrect. The "push" operation is specific to stacks, where it is used for adding elements. In contrast, the operation to add an element to a queue is called "enqueue," not "push." Therefore, the operation "push" is not utilized in queues for adding elements.

The correct answer is To

Key Points

• To field is generally for the main recipients of your email.

• CC stands for carbon copy and BCC stands for blinding carbon copy.
• CC and BCC are both ways of sending copies of an email to additional people.
• It is used to send copies of an email to additional people by specifying multiple addresses in the To field.
• BCC field of a message, those addresses are invisible to the recipients of the email.
• Any email addresses that you place in the To field or the CC field are visible to everyone who receives the message.
• You put four email addresses in the To field or put one email address in the To field and three in the CC field, the four people will all receive the same email.
• They’ll also be able to see the email address of every other recipient in the To and CC fields.

The correct option is 2

CONCEPT:
Try and Except statement is used to handle errors within code in Python.
The code inside the try block will be executed completely whenever there is no error in the program.
And whenever the program encounters an error in the try block, the except block will be executed.
The finally block will always be executed.

Syntax:
try:
# Code
except:
# Execut if an error occurs in the try block
finally:
#Always Executed

Explanation:
Here the first statement in the try block is executed successfully and returns 0 but in the case of exception handling the finally block is always required to be executed.
Thus the finally block will return 2 to the caller and hence 2 will be printed as the output.

A relation is in third normal form, if there is no transitive dependency for non-prime attributes as well as it is in Second Normal Form.
A relation is in 3NF if at least one of the following conditions holds in every non-trivial function dependency X –> Y:

• X is a super key.
• Y is a prime attribute (each element of Y is a part of some candidate key).

In other words, a relation that is in First and Second Normal Form and in which no non-primary-key attribute is transitively dependent on the primary key, then it is in Third Normal Form (3NF).

Table constraints allow you to specify more than one column in a PRIMARY KEY, UNIQUE, CHECK, or FOREIGN KEY constraint definition. Column-level constraints (except for check constraints) refer to only one column.

ALTER table can not change column name. The simplest way to rename a column is to use the ALTER TABLE command with the RENAME COLUMN clause.

If we try to read a text file that does not exist, the file gets created - this is an incorrect statement.

- The provided code has syntax errors that prevent it from running correctly.
- The correct syntax should not have spaces in "x + = 1"; it should be "x += 1".
- The condition "if x % 5 = = 0:" has an extra space, and the correct operator is "==", not "= =".
- Due to these errors, the program will not execute, leading to a syntax error.
- Therefore, the output is "error."

A perfect hash function maps every input key to a unique index in the hash table. If the hash function is perfect, collisions will never occur.

Searching in data structure refers to the process of finding the required information from a collection of items stored as elements in the computer memory. These sets of items are in different forms, such as an array, linked list, graph, or tree.

Alert logs contain important information about error messages and exceptions that occur during database operations.

Packet filter, application gateway, circuit-level gateway, and proxy server are the techniques of firewall.

Email spam, also known as unsolicited bulk email (UBE), or junk mail is the practice of sending unwanted email messages frequently with commercial content in large quantities.

The return type of the input() function is string.

• Statement (A) is correct: A text file stores data as plain text (human-readable), while a binary file stores data in raw bytes (machine-readable).
• Statement (B) is incorrect: The pickle module is used only for binary files, not for text files. It serializes Python objects into binary format.
• Statement (C) is correct: The open() function requires at least the filename to open a file.
• Statement (D) is correct: The "wb" mode (write binary) is used to write data to a binary file.

Thus, the correct answer is (2) (A), (C), and (D) only

In the code shown above, the integer 2 is appended to the list [3,4]. Hence, the output of the code is [3,4,2]. Both variables a and b are local variables.

•  (A) Virus is a self-replicating malicious program that attaches itself to other files to spread, affecting system performance.
•  (B) Trojan Horse is a program that appears legitimate but executes harmful actions in the background, such as stealing data.
•  (C) Spam refers to unsolicited bulk messages, often containing advertisements or phishing links.
•  (D) Firewall is a security system that monitors and controls network traffic, blocking unauthorized access.

Thus, the correct answer is (1) (A) - (IV), (B) - (I), (C) - (III), (D) - (II).

The reference_point is selected by the from_what argument. It accepts three values:
0: sets the reference_point at the beginning of the file.
1: sets the reference_point at the current file position.
2: sets the reference_point at the end of the file.
By default from_what argument is set to 0.

In a star network, every host is connected to a central hub. In its simplest form, one central hub acts as a medium to transmit messages. The star topology reduces the impact of a transmission line failure by independently connecting each host to the hub.

Switch increases the available bandwith of the network. It increases the performance of the network by reducing workload on individual host PCs. Hub is the central point of networking device that connects multiple hosting devices to one network.

The number of computers in Block B1 are greater than any other building and the distance of Block B1 to Blocks B2, B3, and B4 is comparatively less than the distance between any other buildings.

Broadband provides high speed internet access via multiple types of technologies including fiber opitcs, wireless, cable, DSL, and satellite.

Radio waves or radio transmission is used for wide area networks and mobile cellular phones. It can cover larger areas and can penetrate through walls, plants, furniture etc. It is the primary mode of communication and is cheapest of all other modes.

• (A) max() → (II) Returns the maximum value in a column or Series.
• (B) min() → (III) Returns the minimum value in a column or Series.
• (C) mean() → (I) Calculates the arithmetic average of a dataset.
• (D) median() → (IV) Returns the middle value when the dataset is sorted in ascending order.

Thus, the correct answer is (1) (A) - (II), (B) - (III), (C) - (I), (D) - (IV).