CBSE Class 12 Informatics Practices Internet and Web Case Study Questions Set 01

Answer: (b) Star Topology

Explanation:
1. In a star topology every computer is connected by its own cable to a central device (switch or hub).
2. If one computer or its cable fails, only that computer is cut off; all the others keep working.
3. In a bus topology all computers share one backbone cable, so a break in it stops the whole network, and the shared cable slows down as more computers send data.
4. A mesh would need a separate cable between every pair of computers (40 × 39 / 2 = 780 cables), which is not practical for a lab. So the answer is (b) Star Topology.

Teacher's Note:
1. Star topology is the usual choice for a school or office LAN.
2. Its one weak point is the central switch: if that fails, the whole star stops.

Answer: (a) Switch

Explanation:
1. A hub sends every incoming packet to all the computers connected to it.
2. A switch reads the destination address of each packet and forwards it only to the computer it is meant for.
3. Routers and gateways connect different networks; they are not used to connect the computers inside one lab.
4. So the device needed is a (a) Switch.

Teacher's Note:
1. Remember: hub = broadcasts to all, switch = sends only to the intended computer.
2. Because a switch avoids unnecessary traffic, the network also becomes faster.

Answer: (a) Plug ins

Explanation:
1. Plug-ins and add-ons both extend what a browser can do, but they are different.
2. A plug-in is a complete program installed on the computer that the browser uses to handle special content; Flash Player is the standard example of a plug-in used to play videos and animations in a browser.
3. An add-on (extension) is not a complete program; it adds one small feature to the browser itself, such as an ad blocker.
4. Control Panel and Download Settings do not play any content. So the answer is (a) Plug ins.

Teacher's Note:
1. NCERT gives Flash and Java as examples of plug-ins and says a Flash player is needed to play a video in the browser.
2. A plug-in can be used by other applications too, while an add-on works only inside its browser.

Answer: (c) VoIP

Explanation:
1. Skype is used here for a live voice and video call with the classroom in Russia.
2. Carrying voice (and video) calls over the Internet is called Voice over Internet Protocol.
3. So the service being used is (c) VoIP.

Teacher's Note:
1. VoIP calls use the Internet connection instead of the telephone network, so long-distance calls cost very little.
2. Skype, Google Meet and WhatsApp calls are common examples of VoIP.

Answer: (b) 1 - Protocol, 2 - Domain Name

Explanation:
1. Label 1 is over https, the part before ://. It tells the browser which protocol (set of rules) to use, so label 1 is the protocol.
2. Label 2 is over www.cbse.gov.in, the name of the web server that hosts the site. This is the domain name.
3. The rest, /newsite/index.html, is the path of the file on that server.
4. So the answer is (b) 1 - Protocol, 2 - Domain Name.

Teacher's Note:
1. A URL has three main parts: protocol://domain name/path of the file.
2. The browser converts the domain name into an IP address with the help of DNS.

Answer: (d) D

Explanation:
1. A server is the computer that receives requests from other devices and sends back the data they ask for.
2. In the diagram every device (A, B, C, E, F) sends to D and receives from D.
3. So D is the server and the other devices are its clients. The answer is (d) D.

Teacher's Note:
1. The devices that send requests to a server are called clients.
2. A web server is a server that sends web pages to browsers on client devices.

Answer: (b) HTTP response

Explanation:
1. The client (A) sends an HTTP request to the server (D) asking for a web page; that is the arrow from A to D.
2. The server answers by sending the page back to A; that is the arrow from D to A.
3. So the arrow from D to A is an (b) HTTP response.

Teacher's Note:
1. Request goes from client to server; response comes from server to client.
2. Each pair of arrows in the diagram shows one request and its response.

Answer: (d) All of the above

Explanation:
1. Every device that connects to a network or the Internet is given an IP address so that data can reach it.
2. The laptop A, the server D and the mobile phone F are all connected to the network.
3. So all of them have IP addresses. The answer is (d) All of the above.

Teacher's Note:
1. An IP address works like a postal address for a device on a network.
2. Mobile phones get IP addresses too, whether they use Wi-Fi or mobile data.

Answer: (b) Star

Explanation:
1. Each device is connected by its own link to one central device, D.
2. No device is connected directly to another device, and there is no shared cable or closed loop.
3. A layout with every node linked to a central node is a (b) Star topology.

Teacher's Note:
1. Bus uses one shared backbone cable; ring joins the devices in a closed loop.
2. In a star, the failure of one outer device does not affect the others.

Answer: (b) HTTP

Explanation:
1. HTTP stands for HyperText Transfer Protocol.
2. Browsers use it to request web pages, and web servers use it to send them back.
3. FTP is used for uploading and downloading files to a file server, and SMTP is used for sending email.
4. So the answer is (b) HTTP.

Teacher's Note:
1. HTTPS is the secure (encrypted) form of HTTP, shown by a lock sign in the browser.
2. The protocol is the first part of every web address, as in https://www.cbse.gov.in.

Answer: (c) spam

Explanation:
1. Unsolicited means not asked for. Advertising emails sent in bulk to people who never asked for them are called spam.
2. Email services move such mails to a separate Spam folder.
3. So the answer is (c) spam.

Teacher's Note:
1. Never click links or open attachments in spam mails; many are phishing attempts.
2. A newsgroup is an online discussion forum, not advertising mail.

Answer: (b) name@website.info

Explanation:
1. An email address has the form username@domain name, with exactly one @ sign.
2. name@website.info has the user name, then one @, then the domain name website.info.
3. Option (a) has two @ signs, and options (c) and (d) have no @ at all; they look like web addresses.
4. So the answer is (b) name@website.info.

Teacher's Note:
1. The part before @ is the user name; the part after @ is the mail server's domain.
2. Spaces are not allowed in an email address.

Answer: (b) mail server

Explanation:
1. Emails sent to a user are stored on the mail server of the email service provider.
2. When the user wants to read them, the email client (or webmail) connects to that mail server and downloads them.
3. The mail box is the user's storage space on that server, but the client connects to the server itself.
4. So the answer is (b) mail server.

Teacher's Note:
1. SMTP sends mail to the server; POP3 or IMAP is used to fetch mail from the server.
2. Because mail stays on the server, it can be read from any device.

Answer: (b) Email Service Provider

Explanation:
1. An email account is created with a company that provides email, such as Gmail, Outlook or Yahoo.
2. Such a company is called an Email Service Provider.
3. The Internet Service Provider only gives the Internet connection; it is not needed to create an email account.
4. So the answer is (b) Email Service Provider.

Teacher's Note:
1. You can use your Gmail account through any ISP's connection.
2. Registration gives a unique email address and a password to open the mailbox.

Answer: (c) Blind carbon copy

Explanation:
1. Bcc stands for Blind carbon copy.
2. People in the Bcc field get a copy of the mail, but the other receivers cannot see their addresses.
3. So the answer is (c) Blind carbon copy.

Teacher's Note:
1. Cc (carbon copy) receivers are visible to everyone; Bcc receivers are hidden.
2. Bcc is useful for mailing a large group without sharing everyone's address.

Answer: (b) Web browser

Explanation:
1. A web browser is software used to open and view web pages.
2. Google Chrome is such software, like Mozilla Firefox, Microsoft Edge and Safari.
3. So Google Chrome is a (b) Web browser.

Teacher's Note:
1. Google (google.com) is a search engine; Google Chrome is the browser in which it is opened.
2. A website is a collection of web pages, and a browser is needed to view it.

Answer: (c) URL

Explanation:
1. A link (hyperlink) holds the address of the web page it opens.
2. The address of a resource on the web is its URL (Uniform Resource Locator), for example https://www.cbse.gov.in/newsite/index.html.
3. The domain name is only one part of a URL. So the answer is (c) URL.

Teacher's Note:
1. When you point at a link, the browser shows its URL at the bottom of the window.
2. A URL is made of the protocol, the domain name and the path of the file.

Answer: (d) Static

Explanation:
1. A static web page shows the same fixed content to every visitor every time; it changes only when its developer edits it.
2. A dynamic web page changes its content for each user or visit, for example with the user's input.
3. Here the same information is shown every time, so the website is (d) Static.

Teacher's Note:
1. Static pages are usually written only in HTML; dynamic pages use server-side scripts and databases.
2. A results page that shows each student's own marks is an example of a dynamic page.

Answer: (a) sent from a website and stored in user’s web browser while a user is browsing a website

Explanation:
1. A cookie is a small text file that a website sends to the browser while the user visits it.
2. The browser stores it on the user's computer and sends it back on later visits, so the site can remember things such as login status or items in a cart.
3. So the answer is (a) sent from a website and stored in user’s web browser while a user is browsing a website.

Teacher's Note:
1. Cookies can be viewed, blocked or deleted from the browser's privacy settings.
2. Third-party cookies can be used to track a user across websites, which is a privacy concern.

Answer: (b) Hyper Text Markup Language

Explanation:
1. HTML is the language used to create web pages.
2. Its full form is HyperText Markup Language: hypertext is text with links, and markup means tags that describe the content.
3. So the answer is (b) Hyper Text Markup Language.

Teacher's Note:
1. HTML is a markup language, not a programming language.
2. The browser reads the HTML tags and displays the formatted page.