Blockchain Technology Architecture and Platforms 2 — Questions and Answers
Question 1: Which consensus mechanism does Ethereum use after 'The Merge' in 2022?
- Proof of Work
- Proof of Stake (Correct answer)
- Delegated Proof of Stake
- Proof of Authority
Correct answer: Proof of Stake
Ethereum switched from Proof of Work to Proof of Stake during 'The Merge' in September 2022.
Question 2: What is a 'shard' in the context of blockchain scalability?
- A type of cryptographic key
- A partition of the network that processes transactions in parallel (Correct answer)
- A hardware wallet component
- A smart contract storage unit
Correct answer: A partition of the network that processes transactions in parallel
Sharding divides the blockchain network into smaller partitions called shards, each capable of processing transactions independently to improve throughput.
Question 3: What distinguishes a permissioned blockchain from a permissionless one?
- Permissioned blockchains use stronger encryption
- Only approved participants can join and transact on a permissioned blockchain (Correct answer)
- Permissioned blockchains are always faster
- Permissioned blockchains cannot use smart contracts
Correct answer: Only approved participants can join and transact on a permissioned blockchain
A permissioned blockchain restricts participation to pre-approved entities, unlike permissionless blockchains where anyone can join.
Question 4: What is the primary role of a 'validator node' in a Proof of Stake network?
- To mine new blocks using computational power
- To propose and attest to new blocks by staking cryptocurrency as collateral (Correct answer)
- To store the full transaction history only
- To execute smart contracts exclusively
Correct answer: To propose and attest to new blocks by staking cryptocurrency as collateral
Validators in PoS networks lock up (stake) cryptocurrency as collateral and are chosen to propose or vote on new blocks.
Question 5: What is the function of the 'mempool' in blockchain architecture?
- A storage layer for finalized blocks
- A temporary holding area for unconfirmed transactions (Correct answer)
- A memory pool used by smart contracts
- A consensus voting mechanism
Correct answer: A temporary holding area for unconfirmed transactions
The mempool (memory pool) is a node's waiting room where unconfirmed transactions sit until miners or validators include them in a block.
Question 6: Which layer-2 scaling solution batches transactions off-chain and submits compressed proofs to Ethereum?
- State channels
- Sidechains
- ZK-Rollups (Correct answer)
- Plasma
Correct answer: ZK-Rollups
ZK-Rollups bundle many transactions off-chain and submit a zero-knowledge proof to the main chain, inheriting its security while increasing throughput.
Question 7: What is 'finality' in blockchain terminology?
- The last block ever added to a chain
- The point at which a transaction is considered irreversible and permanently recorded (Correct answer)
- The final audit of a smart contract
- The closing of a payment channel
Correct answer: The point at which a transaction is considered irreversible and permanently recorded
Finality means a transaction can no longer be reversed, altered, or cancelled, giving participants certainty that the record is permanent.
Blockchain Technology Architecture and Platforms 2
Which consensus mechanism does Ethereum use after 'The Merge' in 2022?