Computer Science Test - 24

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

Important Points

Browser

• Software that allows users to view web pages.
• A browser is a software application that enables users to access and view web pages on the internet.
• Examples: Google Chrome, Mozilla Firefox, Safari

HTTPS

• The protocol that is used to send data for web pages across the internet.
• HTTPS (Hypertext Transfer Protocol Secure) is a protocol that is used to securely transmit data for web pages over the internet.
• It provides encryption and authentication to protect the integrity and confidentiality of data.
• Example: Accessing a banking website using the "https://" prefix

URL

• A text-based version of a web address.
• URL (Uniform Resource Locator) is a text-based address that specifies the location of a web resource, such as a web page or a file, on the internet.
  • Example: https://www.example.com

Cookie

•  A text file (stored by a web browser) that contains data about a user's browsing preference.
• A cookie is a small text file that is stored by a web browser on a user's device.
• It contains data that websites use to remember user preferences, track user behavior, and provide personalized experiences.
  • Example: Storing login information on a website for automatic sign-in

Based on the explanations above, the correct answer is A - III, B - I, C - IV, D - II.

Concept:

NETWORK DEVICES:

Network devices are to communicate data through different transmission media and to configure networks with different functionality, we require different devices like Modem, Hub, Switch, Repeater, Ethernet Card, Router, Gateway, etc. 

• Modem stands for ‘MOdulator DEModulator’. It refers to a device used for conversion between analog signals and digital bits. 
• An Ethernet card, also known as Network Interface Card (NIC card in short) is a network adapter used to set up a wired network. 
• Repeater data are carried in the form of signals over the cable. These signals can travel a specified distance/

Explanation:

• Bluetooth is a Personal Area Network formed by connecting a few personal devices like computers, laptops, mobile phones, smartphones, printers, etc., All these devices lie within an approximate range of 10 meters. A personal area network may be wired or wireless.

Hence the correct answer is Bluetooth.

The correct answer is LAN.

• Ethernet and token rings are types of LAN (Local Area Network). 
• Token Ring is a computer networking technology used to build LAN. It was introduced by IBM in 1984.
• Ethernet is a family of wired computer networking technologies commonly used in LAN.
• It is also used in metropolitan area networks (MAN) and wide area networks (WAN).
• Ethernet generally uses Bus Topology. 

• The algorithm sorts by comparing each element to the element immediately following it.
• The list needs to be traversed completely for sorting it.
• The control goes up to the (n-1)th element and checks it with the n-th element.
• So, the bubble sort makes a total of n-1 passes.

The correct answer is option C.

Concept:

Mean:

Mean is simply the average of numeric values of an attribute. Mean is also called average.

Definition:

Given n values x1, x2, x3,...xn, mean is compute

Explanation:

The given 10 values are,70, 60, 80, 75, 55, 62, 92, 75, 55, 80 and all students weight are kg.

Mean= (70, 60, 80, 75, 55, 62, 92, 75, 55, 80)/10

Mean= 70.4 kg

Hence the correct answer is 70.4 kg.

Explanation:

• 3 comparisons are required to find the given element.
• Binary search checks the middle element of a sorted list. Depending on whether the target element is lesser or greater than the middle element, the search continues in the left or right half, respectively.

Important Point:

The dry run for binary search on the given list is as follows:

The correct answer is option C.

Concept:

WHERE Clause:

The WHERE clause is used to retrieve data that meet some specified conditions. 

Consider the following relation.

Table: Customers

The IN operator is used with the WHERE clause to match values in a C_country like India or USA.

SQL Query:

Select *

from Customers

where C_Country ='India';

Output:

The select query prints the complete row of the relationship when the condition is true. So when the C_country is 'India' then Customer relation prints the entire row of the database.

Hence the correct answer is C.

The correct answer is option C.

Concept:

The SELECT statement is used to retrieve data from one or more database tables. SELECT * FROM table_name displays data from all the attributes of that table.

Hence the SQL query  Select * from student; prints all the rows and columns of relation student;

Option A, Option B, and Option D print the only one attribute of the relation student which means it prints the only one column of the relation not all columns.

Hence the correct answer is Select * from student;

The correct answer is option B.

Concept:

Renaming of columns:

In case we want to rename any column while displaying the output, we can do so by using the alias 'AS' in the query as:

Example:

Display Employee name as Name in the output for all the employees.

mysql> SELECT EName AS Name FROM EMPLOYEE;

Explanation:

The given SQL query is,

Query:

SELECT Student_name AS Name FROM student;

The above is renamed the specific attribute as Student_name. Hence the student relation attribute student_name changes to name.

The database becomes like below,

Hence the correct answer is the Renaming of columns.

The correct answer is option A.

Concept:

WHERE Clause:

The WHERE clause is used to retrieve data that meet some specified conditions. 

The logical operators AND, OR, and NOT are used with the WHERE clause to combine multiple conditions.

Query:

SELECT * FROM Student WHERE NOT Student_name = 'Anne';

Explanation:

The given relation student, NOT attribute name and where condition checks the whole relation student and prints the except the student name is 'Anne'. And it prints the output like below.