Lesson 4.9.4.10

4.9.4.10 Client server model Quiz: AQA Computer Science, Unit 9

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.9.4.10, Client server model: 20 multiple choice questions for the AQA Computer Science (7517), Unit 9: Fundamentals of communication and networking, written with Revision Ninja.

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The 20 questions

  1. In the client server model, what does the client send and what does the server return?

    • Both sides send requests at the same time and no response is required.
    • The server sends a request message and the client returns a response message to the server, which then closes the connection straight away.
    • The client sends a response, and the server sends the request in return.
    • The client sends a request message and the server responds with a response message.

  2. What does the WebSocket protocol provide?

    • A connection that opens and closes after every single web page request.
    • A full-duplex connection over TCP that stays open, allowing both client and server to send data at any time.
    • A method of sending email messages using a persistent connection to port 25.
    • A one-way connection in which only the server can send data to the client.

  3. Why is WebSocket used in applications such as live chat or live sports scores?

    • Because it stops the client from sending any requests to the server at all.
    • Because the server can push updates to the client immediately, without the client repeatedly asking for them.
    • Because it encrypts every message, which is not possible with ordinary HTTP.
    • Because it stores each message in a database before sending it to the client.

  4. What do the letters in CRUD stand for?

    • Connect, Read, Upload and Download, which are the four operations that a web application uses when it sends files to a server.
    • Create, Retrieve, Update and Delete.
    • Copy, Remove, Undo and Display.
    • Compile, Run, Use and Discard.

  5. In a REST API, which HTTP method maps to the SQL SELECT statement?

    • DELETE
    • GET
    • PUT
    • POST

  6. Which HTTP method is mapped to the SQL INSERT statement in a REST API?

    • PUT
    • GET
    • DELETE
    • POST

  7. Which REST methods map to DELETE and UPDATE?

    • DELETE maps to UPDATE and PUT maps to DELETE, because a delete removes a value from a row while a put adds a brand new row to it.
    • GET maps to DELETE and POST maps to UPDATE.
    • POST maps to DELETE and GET maps to UPDATE.
    • DELETE maps to DELETE and PUT maps to UPDATE.

  8. A JavaScript page needs to fetch a list of products from a server using REST. Which method and SQL statement correspond?

    • POST, which maps to INSERT.
    • PUT, which maps to UPDATE.
    • DELETE, which maps to DELETE.
    • GET, which maps to SELECT.

  9. An API request is made to remove a customer record from the database. Which HTTP method is most appropriate?

    • DELETE
    • POST
    • GET
    • PUT

  10. A REST client needs to change the address stored for an existing customer. Which HTTP method and SQL statement fit this?

    • POST, which maps to an SQL INSERT statement.
    • GET, which maps to an SQL SELECT statement.
    • PUT, which maps to an SQL UPDATE statement.
    • DELETE, which maps to an SQL DELETE statement.

  11. Which format is easier for a human to read than XML and is more compact?

    • YAML with full document markers
    • XML with nested tags and namespaces
    • JSON (JavaScript Object Notation)
    • Binary data stored in a packed format

  12. Which JSON fragment represents a single customer with a name and an age?

    • customer(name=Ada, age=36)
    • <customer><name>Ada</name><age>36</age></customer>
    • {"name": "Ada", "age": 36}
    • name Ada age 36 end

  13. Why is JSON generally quicker for a computer to parse than XML?

    • It is stored in a relational database, which removes the need for parsing.
    • It is always compressed by the browser before being sent over the network, which is why it is always smaller than the equivalent XML.
    • It uses binary encoding so that no characters need to be read at all.
    • It has less markup overhead, so fewer characters must be read and interpreted.

  14. What does REST stand for?

    • Relational Entity Storage and Transfer
    • Representational State Transfer
    • Remote Execution of Structured Tasks
    • Real-time Event Stream Transport

  15. In a web application, what runs in the browser and what runs on the server?

    • Neither runs on the server, as all data is stored in the HTML file.
    • JavaScript in the browser calls an API that runs on the server.
    • The API runs in the browser and the JavaScript runs on the server.
    • Both the JavaScript and the API run only on the user's device.

  16. Which format is commonly used to send data between a REST API and a web application's JavaScript?

    • JSON
    • Plain text with no structure
    • Source code of a compiled program
    • Raw binary images only

  17. Why would a live chat application use WebSocket instead of repeated HTTP requests?

    • Because HTTP cannot send any data from the client to the server.
    • Because WebSocket stores each message in a local file on the client.
    • A persistent full-duplex connection avoids constant new requests and lets the server push messages to clients.
    • Because WebSocket is the only protocol that can carry text messages at all.

  18. In the client server model, which component starts an exchange?

    • Whichever side has the larger amount of data.
    • The server.
    • The router that connects the two.
    • The client.

  19. Why should a web application use POST rather than GET to add a new record?

    • GET requests cannot be sent by a JavaScript program running in a browser.
    • GET is encrypted by default, so it cannot be used for sensitive data.
    • GET is limited to 1 kilobyte of data, so POST is always needed for records.
    • GET is intended to retrieve data without changing the server, whereas POST is used to create a new resource.

  20. What is the main difference between a WebSocket connection and a standard HTTP exchange?

    • A WebSocket cannot carry text while HTTP can carry only binary files.
    • A WebSocket sends only encrypted data while HTTP sends only plain text.
    • A WebSocket uses port 25 while HTTP uses port 80 for all of its messages.
    • A WebSocket keeps one connection open for two-way messages, whereas HTTP follows a request and response pattern for each exchange.

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