Blockchain Developer Blockchain Scalability and Layer 2 Solutions

Question 1

What is the primary goal of Layer 2 (L2) scaling solutions in blockchain?

Accepted Answer

To increase transaction throughput while inheriting security from the base layer

Answer

To replace the base layer blockchain entirely

Answer

To create independent blockchains with no connection to Layer 1

Answer

To reduce the number of nodes required to run a blockchain

Question 2

Which Layer 2 solution was designed specifically to scale Bitcoin by enabling off-chain payment channels?

Accepted Answer

Lightning Network

Answer

Polygon

Answer

Optimism

Answer

Plasma

Question 3

What is a state channel in the context of blockchain scalability?

Accepted Answer

An off-chain communication channel where participants exchange signed state updates without touching the blockchain for each transaction

Answer

A channel that broadcasts state changes to all network nodes simultaneously

Answer

A sidechain that mirrors the main chain state

Answer

A smart contract that manages on-chain governance voting

Question 4

In Optimistic Rollups, how is transaction fraud prevented?

Accepted Answer

A challenge period allows validators to submit fraud proofs if invalid transactions are detected

Answer

Zero-knowledge proofs are submitted with every transaction batch

Answer

All transactions are verified by a committee of trusted nodes before submission

Answer

Transactions are re-executed on Layer 1 immediately upon submission

Question 5

What is database sharding as applied to blockchain scalability?

Accepted Answer

Splitting the blockchain's validator set into smaller groups that process different transaction subsets in parallel

Answer

Compressing block data to reduce storage requirements

Answer

Dividing smart contract logic across multiple contracts

Answer

Routing transactions to different Layer 2 chains based on fee

Question 6

Which type of rollup uses cryptographic validity proofs to immediately finalize transaction batches on Layer 1?

Accepted Answer

ZK-Rollups

Answer

Optimistic Rollups

Answer

Plasma Rollups

Answer

State Channel Rollups

Question 7

What is the main security trade-off when using a sidechain compared to the Ethereum mainnet?

Accepted Answer

Sidechains rely on their own consensus mechanism and validator set, which may be less decentralized or secure than the main chain

Answer

Sidechains have higher gas fees than mainnet

Answer

Sidechains cannot support EVM-compatible smart contracts

Answer

Sidechains require zero-knowledge proofs for every transaction