NEW
Font size
WorksheetsBlockchain and Web2 Fundamentals Quiz
Total questions: 25
Worksheet time: 13mins
What best describes a blockchain?
A centralized database controlled by one organization
A distributed ledger where records are linked using cryptographic hashes
A cloud storage service for files
A programming language for finance
Why is a cryptographic hash important in blockchain?
It compresses data to reduce storage
It makes blocks editable by anyone
It ensures integrity by detecting any change in data
It increases internet speed
What happens if a transaction inside a block is modified?
Nothing changes
The block hash changes, breaking the chain linkage
Only the wallet balance changes
Mining becomes faster
What is the primary purpose of a consensus mechanism?
To make websites interactive
To synchronize nodes and agree on the valid state of the ledger
To store images efficiently
To generate private keys
Proof of Work (PoW) mainly relies on:
Voting by token holders
Solving computational puzzles
Government verification
Central server approval
A major drawback of Proof of Work is:
Lack of cryptography
High energy consumption
No decentralization
No security
What is a 51% attack?
When a user forgets password
When majority network power controls transaction ordering and double spending
When smart contract fails
When blockchain becomes faster
What does “immutability” mean in blockchain?
Data can be easily deleted
Data can be changed anytime
Once confirmed, altering records is extremely difficult
Data is stored in Excel
What is a smart contract?
A PDF agreement signed digitally
A self-executing program stored and run on a blockchain
A banking app
A server-side script only
What is “gas” in Ethereum?
Fuel for mining hardware
A transaction fee paid to execute operations on Ethereum
A token used only for NFTs
Free cost for transactions
Which is NOT typically stored in a blockchain block header?
Previous block hash
Timestamp
Merkle root
User’s password
What is a Merkle Tree used for?
To speed up video streaming
To verify large sets of transactions efficiently
To generate private keys
To encrypt the entire blockchain
A node in blockchain is:
A type of cryptocurrency
A computer/device participating in the blockchain network
A private key
A smart contract function
What is a key difference between Public and Private blockchains?
Public blockchains require no internet
Private blockchains allow only permissioned participants
Public blockchains are always faster
Private blockchains have no consensus
What is the role of a private key?
It is used to receive funds publicly
It signs transactions to prove ownership
It stores blockchain blocks
It encrypts the website frontend
In Web2, the main architecture is usually:
Peer-to-peer only
Client-server architecture
Blockchain-based architecture
Offline-first architecture
What is the purpose of DNS?
To encrypt data
To translate domain names into IP addresses
To store cookies
To create blockchain blocks
What does REST API mainly use?
Only UDP protocol
HTTP methods like GET, POST, PUT, DELETE
Blockchain consensus
Only WebSockets
Which HTTP status code means “Not Found”?
200
201
404
500
Which HTTP method is typically used to update an existing resource?
GET
PUT
TRACE
CONNECT
What does authentication mean?
Checking if user has permission
Verifying the identity of a user
Encrypting the database
Loading the website faster
What does authorization mean?
Verifying identity
Granting permissions/access rights
Deleting cookies
Creating a wallet
Which is a common Web2 security vulnerability?
Hash chaining
XSS (Cross-Site Scripting)
Proof of Stake
Merkle root
Why is HTTPS preferred over HTTP?
It reduces server cost
It provides encryption + integrity using TLS
It makes websites decentralized
It stores blockchain keys
What is the main limitation of Web2 platforms (like Instagram/YouTube)?
No backend exists
Users cannot upload content
Data ownership and control remains with centralized platforms
APIs cannot be built
