Computer Science: CUET Mock Test - 6 - CUET MCQ

Normalization is a process that is used to eliminate redundant data and to ensure that data is stored in a way that minimizes data dependency. It involves dividing a larger table into smaller tables and defining relationships between them to reduce data redundancy and improve data integrity.

The correct answer is WiMax

Key Points

• WiMax stands for Worldwide Interoperability for Microwave Access.
• It's a wireless technology designed to provide broadband internet access over a large area.
• Wi-Fi, while also wireless, offers connectivity to a local network with a shorter range.

The correct answer is B, D and E only

Key PointsGuided media refers to physical cables or wires that confine and direct the transmission of signals. These cables provide a structured pathway for data to travel, ensuring reliability and protection from interference. Here's a breakdown of the options:

• A. Radio Waves: Radio waves are a form of unguided media, meaning they travel freely through the air or space.
• B. Optical fiber: This is a type of guided media that uses light pulses to transmit data. It offers high bandwidth and resistance to interference.
• C. Microwaves: Similar to radio waves, microwaves are unguided media used for short-range wireless communication.
• D. Twisted pair: This is a common type of guided media consisting of two insulated copper wires twisted together. It's widely used in telephone and Ethernet networks.
• E. Coaxial cable: Another guided media option, coaxial cable has a single copper conductor surrounded by an insulating layer and a braided metal shield. It provides better protection against interference compared to twisted pair.

In conclusion, only optical fiber, twisted pair, and coaxial cable are examples of guided media because they act as physical channels for data transmission.

The correct answer is Binary search

Key Points

• Binary Search: Quickly narrows down search by discarding half the list at each step based on the target's comparison with the midpoint element.
• Median (even elements): Points to the middle two elements, whose average is the median.

Additional Information

• Linear Search (or Sequential Search): Examines each element in the list sequentially until the target is found or the entire list is traversed. The order doesn't affect its performance.
• Insertion Sort: Elements are inserted into their correct positions in a step-by-step manner, independent of the list's midpoint.

The correct answer is D→B→A→E→C

Key Points

​Insertion sort works by iterating over each element in the list starting from the second element. For each element, it compares it to the previous elements and inserts it into the correct position in the sorted subarray on its left.

Statement-1: This should be a loop over the indices of the list starting from 1 to n-1. The range function returns a sequence of numbers, so range(n) would be appropriate.

• Correct option: D
• The loop should be for i in range(n):

Statement-2: Before we start comparing the element at the current index i with the elements before it, we need to store its value in a variable. We call this temp.

• Correct option: B
• temp = list3[i]

Statement-3: The while loop condition must ensure that it runs as long as j is non-negative and the current element (pointed by temp) is less than list3[j].

• Correct option: A
• while j >= 0 and temp < list3[j]:

Statement-4: If the condition in the while loop is true, shift list3[j] one position to the right (i.e., to index j+1), and decrement j to continue comparing temp with the next element on the left.

• Correct option: E
• j = j - 1

Statement-5: Finally, insert temp in its correct position in the sorted subarray. This position is j + 1 because j was decremented one extra time in the while loop.

• Correct option: C
• list3[j + 1] = temp

Putting all of these together, the correct sequence of statements is: D→B→A→E→C

The correct answer is A, B and D only

Key Points

• A. closed - This is an attribute that indicates whether the file is closed or not. If the file is closed, it returns True; otherwise, it returns False.
• B. mode - This attribute represents the mode in which the file was opened, such as 'r' for reading, 'w' for writing, etc.
• C. next - This is not an attribute of a file object; it refers to a built-in function in Python that retrieves the next item from an iterator.
• D. name - This attribute holds the name of the file.
• E. tell - This is not an attribute but a method of a file object that tells you the current position within the file.

Therefore, the attributes of a file object include closed, mode, and name, making the correct choice 4) A, B, and D only.

Concept:

Aggregate functions return a single result row based on groups of rows, rather than on single rows. Aggregate functions can appear in select lists and in ORDER BY and HAVING clauses.

Key Points

In SQL, AVG is an aggregate function

The correct option is (2)

ID

Concept:-

Here the ID is the only attribute that can be assumed as a primary key in this scenario. Other attributes are not valid choices.

Explanation:

Let me take an example to clarify the above statement.

Consider that the ID attribute is unique to every employee. In that case, we can say that the ID attribute can uniquely identify the tuples of this table, and it can be treated as a primary key. The primary key is a minimal super key, consequently, ID is also a super key.

Key Points

• A group of one or more columns (attributes) used to specifically identify rows in a database is known as a super key.
• The super key is created by adding 0–more attributes to the candidate key. Super keys are candidate keys, but the opposite is not true.
• An alternate key serves as an alternate unique identifier for each entity instance in addition to the primary key.
• To get records from tables, super keys and candidate keys are both used. The associations between tables are also established using these keys.

Note: If any attribute is combined with candidate or primary key, then the combination becomes super key. Hence the given option 4 (CITY, ID) can also be a valid answer. But as per the official answer, option 2 is correct.

Answer: Option 3

Concept:

Quick sort:

• Quicksort is an efficient sorting algorithm also known as a partition-exchange sort
• Quicksort is a comparison sort, meaning that it can sort items of any type for which a "less-than" relation is defined
• Quicksort is a divide-and-conquer algorithm in which the pivot element is chosen, and this pivot element reduced the given problem into two smaller set
• In the efficient implementations, it is not a stable sort, meaning that the relative order of equal sort items is not preserved
• Quicksort can operate in place on an array, requiring small additional amounts of memory to perform the sorting.

In Quicksort, the worst-case takes Θ (n2) time. The worst case of quicksort is when the first or the last element is chosen as the pivot element.

This will give Θ (n2) time complexity.
Recurrence relation for quick sort algorithm will be,
T (n) = T (n - 1) + Θ (n)
This will give the worst-case time complexity as Θ (n2).

Merge sort:

• Merge sort is an efficient sorting algorithm that uses a divide-and-conquer approach to order elements in an array.
• Mergesort has two steps:
  • Merging
  • Sorting.

• The algorithm uses a divide-and-conquer approach to merge and sort a list.

The recursive mergesort algorithm is
1. If the list has only one element, Return the list and terminate. (Base case)
2. Split the list into two halves that are as equal in length as possible. (Divide)
3. Using recursion, sort both lists using mergesort. (Conquer)
4. Merge the two sorted lists and return the result. (Combine).

In Merge sort, the worst-case takes Θ (n log n) time. Merge sort is based on the divide and conquer approach. It is out of place sorting algorithms

Recurrence relation for merge sort will become:
T(n) = 2T (n/2) + Θ (n)
T(n) = n + Θ (n)
T (n) = n × logn

Selection sort:
Algorithm:

• Find the smallest item in the list, and exchange it with the leftmost unsorted element.
• Repeat the process from the first unsorted element.

Insertion sort:

In Insertion sort, the worst-case takes Θ (n2) time, the worst case of insertion sort is when elements are sorted in reverse order. It is an in-place sorting algorithm.

In that case, the number of comparisons will be like:

This will give Θ (n2) time complexity.

The correct answer is Firewall

Key Points

Firewall -

• A firewall is a network security system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules.
• It establishes a barrier between a trusted, secure internal network and another network (for example, the internet) that is not assumed to be secure and trusted.
• Its main purpose is to control the incoming and outgoing network traffic by analyzing the data packets and determining whether they should be allowed through or not.

Additional Information

Router -

• A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the internet.
• When connected to the internet, they route data to the appropriate locations essentially managing the flow of data in a network.

Cache server -

• A cache server is a dedicated server acting as a storage for web content, that can be served up quickly to users.
• Cache servers save web, computing and database pages in memory or into its hard drive so that the next time a user requests that page, the message sends quicker.
• It is a type of hardware that can help a network run more efficiently by storing recently or frequently requested data to quickly provide it if requested again.

Proxy server -

• A proxy server serves as a gateway between the user and the internet. It's an intermediary server separating end users from the websites they browse providing varying levels of security, functionality, and privacy depending on requirements.
• Proxy servers can also censor web content or store copies of web content to speed up retrieval. It can even provide anonymity to users by masking their IP addresses.

The correct answer is All of these

Key Points

• Simplex Communication: This is a one-way communication where one party can send data but cannot receive, like a radio or television broadcast.
• Duplex Communication: This allows for two-way communication, with both parties able to send and receive data simultaneously, like a telephone conversation.
• Half-Duplex Communication: This is also a two-way communication but not at the same time. When one party sends data, the other can only receive it, and vice versa. Walkie-talkies are a good example of this mode of communication.

A single row of a table, which contains a single record for that relation is called a tuple.

A repeater is a device that operates only in the physical layer. Signals that carry information within a network can travel a fixed distance before attenuation endangers the integrity of the data.

The strupr( ) function is used to convert a given string to uppercase.

A network packet is a formatted unit of data carried by a packet-switched network. Computer communications links that do not support packets, such as traditional packet switching, simply transmit data as a bit stream. When data is formatted into packets, the bandwidth of the communication medium can be better shared among users than with circuit switching. A packet consists of control information and user data, which is also known as the payload. Control information provides data for delivering the payload, for example: source and destination network addresses, error detection codes, and sequencing information. Typically, control information is found in packet headers and trailers.

Option 1 is the correct answer. The address range of this class is from 128.0.0.0 to 191.255.255.255.

Statement I is correct. Hashing technique is very fast and efficient for large collections, but requires additional memory to store the hash table. Statement II is a fact for Linear Search not for a Binary Search. Binary Search technique reduces the search space by half at each step, making it faster than linear search for larger collections.

Opening a CSV file is simpler than you may think. In almost any text editor or spreadsheet program, just choose File > Open and select the CSV file.

• Join command combines rows from two or more tables.
• Group By command groups the result set by specified columns.
• Order By command sorts the result set based on a specified column.
• Where clause filters the result set based on specified conditions.

Sorting is the process of arranging data into meaningful order so that you can analyze it more effectively.

The ''/'' operator cannot be used with string data type, while the rest three can be used for strings data type.

Option 1 is the correct answer.
Exception handling in Python allows for graceful recovery from errors and prevents program crashes. When an error occurs during program execution, Python's exception handling mechanism allows the program to gracefully handle the error and take corrective action, rather than crashing the program entirely. This can be achieved by wrapping potentially error-prone code in a try-except block, where the except block catches any exceptions that are raised and takes appropriate action.

Database management systems are intended to eliminate data redundancy, establish relationships among records in different files and manage file access. Since all of the given options are true, option 4 is the correct answer.

Dos attack is the type of attack intended to make resources or service unavailable to its intended users. Such DOS attacks are carried out on websites to stop them from functioning.

The most reliable way to make sure you are safe is to open an email attachment or click on a link is to scan it with anti-virus software.

'tup1[2]=20' will make an error.
Here, the first option 'print(tup1[2])' will display the value at the position.
Therefore, print(tup1[2])=25. The starting position is 0.
print(min(tup1)) will display the minimum value in that tuple.
Here, print(min(tup1))=10
print(len(tup1)) will give output as the tuple length.
print(len(tup1)) = 4
But, tup1[2]=20 means assigning a new value to the position.
In tuples, values are constant.
So, tup1[2]=20 will result in an error.

In a relational database, a primary key is a unique identifier for each record in a table. A primary key cannot be null, and it must have a unique value for each record in the table. The primary key is used to identify each record in the table and to ensure data integrity by preventing duplicate records from being inserted into the table. Therefore, the reason does not correctly explain the assertion.

• There are some codes to handle a file in a programming language.
• myfile=open('student. txt', 'w') is the mode that allows opening a file in write mode.
• myfile=open('student.txt', 'r') is the mode that open file in only read mode.
• myfile= open ('student.txt') is also allowed to open in reading mode.

The pickle module implements binary protocols for serializing and de-serializing a Python object structure.

Here, Check will be treated as a string, not a tuple, as there is no comma after the element.