Computer Science: CUET Mock Test - 1 - CUET MCQ

Python is an interpreted, object-oriented, high-level programming language with dynamic semantics.

The correct answer is Statement I is incorrect but statement II is true

Key Points

• The mode is the value that appears most frequently in a set of data, not the middle value when sorted. So, Statement II accurately describes the mode.

The correct answer is Bubble sort

Key Points

• Bubble sort works by repeatedly comparing adjacent elements and swapping them if they are in the wrong order. This process continues until the list is sorted.

Additional Information

• Insertion sort: Insertion sort builds the sorted list one element at a time. It compares each element with the sorted portion of the list and inserts it at the correct position.
• Selection sort: Selection sort finds the minimum (or maximum) element in the unsorted part of the list and swaps it with the first element. This process continues until the list is sorted.
• Adjacent sort: There is no sorting technique called "adjacent sort."

The correct answer is A and B only

Key Points

• A. Queue is an ordered linear data structure (CORRECT)
  • Queues follow a specific order, adhering to the FIFO (First-In-First-Out) principle.
  • Elements are arranged linearly, one after the other.
• B. Deque can support both stack and queue operations (CORRECT)
  • Deque (double-ended queue) allows insertion and deletion at both ends, making it flexible.
  • It can mimic stack behavior by performing operations at one designated end.
• C. Queue is a non-linear data structure (INCORRECT)
  • As mentioned earlier, queues maintain a linear order of elements.
• D. Queue works on FILO principle (INCORRECT)
  • Queues operate on FIFO, meaning the first element added is the first one removed.
  • FILO (First-In-Last-Out) describes stacks, where the last element added is accessed/removed first.
• E. Deque is a version of Queue which does not allow insertion and deletion at both ends (INCORRECT)
  • The defining characteristic of a deque is its ability to perform operations at both ends, unlike a standard queue (insertion at rear, deletion from front).

Therefore, the correct answer is 2) A and B only.

The correct answer is 0

Key Points

• file-object.seek(offset, [reference point]) is a method used to move the file pointer to a specific position within a file.
• offset is the number of bytes to move the pointer.
• reference point is an optional argument that specifies where to start the offset count. If omitted, it defaults to 0.

Values for reference point:

• 0: Seeks from the beginning of the file.
• 1: Seeks from the current position of the file pointer.
• 2: Seeks from the end of the file.

Important Points

• The default reference point of 0 makes it convenient for common scenarios where you want to start seeking from the beginning of the file.
• Understanding the reference point options allows for precise control over file pointer positioning.

The correct answer is Fl.readline()

Key Points1) Fl.readlines()

• It reads all lines of the file into a list of strings, not just the next line.
• It's less efficient if you only need to read one line at a time, as it loads the entire file into memory.

3) Fl.readnext()

• This method doesn't exist in most programming languages.

4) Fl.read()

• It reads all the content of the file from the current position to the end as a single string.
• It's not suitable for reading individual lines separately.

Fl.readline() is specifically designed to read the next line from a file object and return it as a string. It's the most efficient way to read lines sequentially and process them one at a time.

Example:

Important Points

• Use with open(...) to ensure proper file closing.
• Call Fl.readline() repeatedly to read lines one by one.
• Check for empty strings to detect the end of the file.

The correct answer is After an exception is raised but before it is executed.

Key PointsThe search for an appropriate exception handler occurs after an exception is raised but before the handler’s code is executed. This step is crucial for determining the appropriate course of action to manage or address the error.

The correct option is Syntax Error

CONCEPT:

Syntax errors occur when the programmer does not follow or makes mistake in the syntax of a particular programming language

Common syntax errors in python:

• leaving out a keyword.
• misspelling a keyword.
• leaving out a symbol, such as a comma, brackets....etc.

In Python, assignment using `=` operator is not allowed inside an condition of if statement

The error thrown will be "SyntaxError: invalid syntax. Maybe you meant '==' or ':=' instead of '=' ".

Syntax of if statement in python:

if condition:

# code to execute in case if the above condition is true

Additional Information

IOError is raised when an input/output operation fails.

The correct answer is A - IV, B - II, C - III, D - I

Key Points

• A-IV) length() - Returns the number of characters in a string.
• B-II) lower() - Converts all characters in a string to lowercase.
• C-III) concat() - Concatenates two or more strings into one string.
• D-I) position() - Finds the position of a substring within a string.

Each function in SQL has a specific purpose regarding string manipulation.

• length() is used to determine the length of a string, telling us how many characters it contains.
• lower() is utilized to convert every character in a string to its lowercase variant, which is useful for case-insensitive comparisons.
• concat() combines two or more strings into a single string, allowing for the construction of new strings from existing ones.
• Lastly, position() is employed to find the starting position of a specified substring within another string, which can be crucial for substring analysis and manipulation.

The correct answer is (I) and (II) are true
Concept:
Statement 1: A super key is an attribute or combination of attributes that uniquely identify records in an RDBMS table.
True, A super key, or just key, is a combination of every attribute that may be used to specifically identify rows (or tuples) in a database. This indicates that a superkey may contain additional information that isn't required for uniquely identifying table rows.
Statement 2: A candidate key is a subset of a super key.
True, A Candidate key is a subset of Super keys and is clear of any unnecessary attributes that are not essential for tuple identification. For all tuples, the Candidate key value is distinct and non-null. Additionally, each table must include at least one Candidate key.
Statement 3: All super keys are candidate keys but vice versa is not true.
False, Candidate keys are a subset of Super keys. They contain only those attributes which are required to uniquely identify tuples. All Candidate keys are Super keys. But the vice-versa is not true.
Hence the correct answer is (I) and (II) are true.

Python uses indentations to define blocks of code. Indentations are simply spaces or tabs used as an indicator that is part of the indent code child, as used in curly braces C, C++, and Java which uses curly braces {}.

• A foreign key is a field in one table that refers to the primary key in another table, ensuring referential integrity by preventing invalid data in relationships.

In Python, the '/' operator is for numerical division and cannot be used with strings. However, '+' concatenates strings, '*' repeats a string, and 'in' checks for substring membership.

readline() reads the next line from a file object and returns it as a string, including the newline character if present. In contrast, readlines() reads all lines into a list, read() reads the entire file, and read(2) reads 2 bytes.

The false statement is B. A Python 'while' loop executes a block of statements repeatedly as long as the condition is true, stopping when it becomes false—not when it becomes true. A and C correctly describe loops, and D is true as 'for' loops can iterate over lists.

Pickle in Python is primarily used in serializing and deserializing of a Python object structure. In other words, it's the process of converting a Python object into a byte stream to store it in a file/database, maintain program state across sessions, or transport data over the network.

A queue operates on the First In, First Out (FIFO) principle. Insertions occur at the rear end, and deletions occur at the front end.

The tell() method returns the current position of file object. This method takes no parameters and returns an integer value. Initially file pointer points to the beginning of the file (if not opened in append mode). So, the initial value of tell() is zero.

Data processing refers to the manipulation of data by a computer, such as calculations or transformations, distinguishing it from utilizing, batching, or upgrading.

A database management system (DBMS) ensures database security (protecting data from unauthorized access) and integrity (maintaining data accuracy and consistency) through access controls and validation.

A firewall monitors network traffic and can help protect a server hosting online images by blocking unauthorized access, though additional measures like encryption are often used specifically for images.

Circuit switching establishes a dedicated path, making it well-suited for voice communication (e.g., telephone networks). Packet switching sends data in packets across multiple paths, ideal for data and non-voice communication (e.g., the internet).

A tuple is a collection of Python objects separated by commas and enclosed in parentheses ().

For example, L = (1, 'Python', '3.14') is a tuple, not a list, dictionary, or string.

Mode 'a' opens a file for appending. The file pointer is placed at the end of the file, if the file exists. If the file does not exist, it creates a new file for writing.

Correct code for statement 3 is cw.writerow (['Title', 'Author', 'Price']) where, Title, Author and Price are the columns. writerow () method is used to write single row at a time.

To check if Title (first column, index 0) starts with 'R', use r[0][0] == 'R' for the first character

csv. writer is used to insert data to the CSV file. This class returns a writer object which is responsible for converting the user's data into a delimited string.
Syntax CSV.writer (CSVfile)
In statement 2, missing code is CSV. writer (csvf) where, csvf is CSV file.

Since row is a list containing all the values of a record, the best way to print it as a string is to use ",".join(row), which joins the list elements with commas.

print(",".join(row))

This ensures that the output looks like a proper CSV row.

Intellectual property rights:

• Intellectual property rights (IPR) refer to the legal rights given to the inventor or creator to protect his invention or creation for a certain period of time. Intellectual Property is legally protected through patents, trademarks, copyrights, trade secrets, etc.​ 

Copyright:

• Copyright grants legal rights to creators for their original works like writing, photograph, audio recordings, video, sculptures, architectural works, computer software, and other creative works like literary and artistic work. 

Patent:

• A patent is usually granted for inventions. Unlike copyright, the inventor needs to apply (file) for patenting the invention.

Trademark:

• A trademark includes any visual symbol, word, name, design, slogan, label, etc., that distinguishes the brand or commercial enterprise, from other brands or commercial enterprises.

Hence the correct answer is All the above.

Concept:
The given code is,
a = 10
b = 0
c = a/b
print(c)
A number must be divided by another number that is not zero. If we write a simple program that divides an integer by zero, the Python interpreter will throw a ZeroDivisionError. This error will occur if the division denominator is set to zero.
Hence it throws the ZeroDivisionError.
Hence the correct answer is ZeroDivisionError.