Ethereum Developer Ethereum Upgrades and Layer 2 Scaling

Question 1

What major change did the Ethereum Merge (2022) introduce?

Accepted Answer

Replaced Proof of Work with Proof of Stake consensus

Answer

Increased the block size to reduce fees

Answer

Implemented sharding for parallel transaction processing

Answer

Merged Ethereum mainnet with Polygon

Question 2

What is EIP-1559 and what problem does it address?

Accepted Answer

A fee market reform that introduced a base fee burned per transaction, reducing fee unpredictability

Answer

A proposal to double the block gas limit for scalability

Answer

A standard for gasless meta-transactions

Answer

An upgrade that enabled smart contracts on the Beacon Chain

Question 3

What is an Ethereum layer-2 (L2) solution?

Accepted Answer

A protocol built on top of Ethereum that processes transactions off-chain while inheriting mainnet security

Answer

A sidechain that runs independently with its own consensus

Answer

An alternative client implementation of the Ethereum node

Answer

A smart contract upgrade mechanism for existing dApps

Question 4

What is the fundamental difference between Optimistic Rollups and ZK Rollups?

Accepted Answer

Optimistic Rollups assume validity and use fraud proofs; ZK Rollups use cryptographic validity proofs

Answer

ZK Rollups are faster to withdraw from than Optimistic Rollups

Answer

Optimistic Rollups use Ethereum data availability; ZK Rollups store data off-chain

Answer

ZK Rollups require sequencer decentralization; Optimistic Rollups do not

Question 5

What does 'data availability' mean in the context of Ethereum rollups?

Accepted Answer

Ensuring that the transaction data needed to reconstruct rollup state is accessible to anyone

Answer

The uptime guarantee of an Ethereum RPC provider

Answer

The percentage of nodes that have synced the latest block

Answer

The availability of historical event logs on a node

Question 6

What is a sequencer in a rollup network?

Accepted Answer

A centralized or decentralized node that orders and batches transactions before posting them to L1

Answer

A smart contract that verifies ZK proofs on Ethereum

Answer

A validator node that proposes new Ethereum blocks

Answer

A relay that bridges assets from L1 to L2