Ethereum Consensus Mechanisms Quiz

1. What is a consensus mechanism?

• A method for donating to charitable causes through cryptocurrency.
• A system for creating art and music using blockchain technology.
• A protocol that allows a network of nodes to agree on the state of a blockchain.
• A type of computer virus that affects blockchain networks.

2. How do nodes input data in a consensus mechanism?

• Nodes input data from a pending transaction and report back with an approval or disapproval status once the request is cross-checked with its records.
• Nodes input data independently and make decisions without consulting the network.
• Nodes input data solely from external sources without verification.
• Nodes input data based on random selections from previous transactions.

3. What happens if a node wants to challenge the record in a consensus mechanism?

• The node would simply abandon the transaction request.
• The node would override the record without consensus.
• The node would have to request a network-wide recall.
• The node would automatically accept the record without validation.

4. What is an example of consensus mechanisms in action?

• The way humans agree on the rules of a game.
• A committee vote on a school project.
• A market trading competition.
• A court ruling on a legal case.

5. What is Proof of Work (PoW)?

• A method for speeding up transaction processing without the need for miners.
• A technique used to increase the number of transactions per second on a network.
• A process used in some public blockchains to validate transactions by demonstrating that a program did the work required to propose a new block for the chain.
• A system for enhancing user privacy by hiding transaction details.

6. How does Proof of Work work in Bitcoin?

• Miners collaborate to share resources and validate transactions efficiently as a group.
• Miners randomly generate blocks and validate transactions without any computational effort.
• Miners trade off their computational resources to bypass complex problems entirely.
• Miners compete to solve a math puzzle until a lower value than the difficulty target is found.

7. What are the four fields in a block header in Bitcoin?

• Software version, previous block`s hash, Merkle root, timestamp
• Network version, difficulty level, timestamp, validator ID
• Block height, node ID, transaction count, gas limit
• Transaction data, block size, miner`s address, fees

8. What is the difference between Proof of Work and Proof of Stake?

• Proof of Work uses computational power to validate transactions, while Proof of Stake uses validators who offer ether as collateral to validate transactions.
• Proof of Work allows instant transaction confirmation, while Proof of Stake requires waiting for multiple validations.
• Proof of Work is based on random selection, while Proof of Stake involves solving complex equations.
• Proof of Work and Proof of Stake are the same in validating blockchain transactions.

9. How does Ethereum validate transactions?

• Ethereum uses random selection of nodes to validate transactions without rewards.
• Ethereum uses a proof-of-stake-based consensus mechanism where validators create blocks and are rewarded in ETH.
• Ethereum uses a centralized model where a single entity approves all transactions.
• Ethereum uses a proof-of-work consensus mechanism where miners solve puzzles to create blocks.

10. What is the incentive structure for validators in Ethereum?

• Validators are incentivized with rewards and penalties applied to capital locked by stakers, encouraging honest operation and punishing dishonest behavior.
• Validators earn rewards only if they cease all operations and do not participate in the consensus mechanism.
• Validators receive fixed income regardless of their honesty, removing any motivation to operate reliably.
• Validators gain bonuses based on the amount of computing power they contribute to the network.

11. How does Ethereum select honest validators?

• Validators are selected based on a protocol that governs how honest validators are chosen to propose or validate blocks, process transactions, and vote for their view of the head of the chain.
• Validators are chosen randomly from all network participants regardless of their stakes.
• Validators are picked based on their transaction volume in the network.
• Validators are selected by public vote from all Ethereum users every month.

12. What is the fork-choice mechanism in Ethereum?

• The fork-choice mechanism is used to randomly choose which transactions to include in a block.
• The fork-choice mechanism determines which miners will create new blocks in Ethereum.
• The fork-choice mechanism selects blocks that form the `heaviest` chain based on validator votes.
• The fork-choice mechanism selects the first block created in each epoch of the blockchain.

13. What was Ethereum`s previous consensus mechanism?

• Proof of History
• Delegated Proof of Stake
• Proof of Work
• Proof of Authority

14. How did Ethereum transition from PoW to PoS?

• Ethereum changed from PoW to PoS through a hard fork on January 1, 2023.
• Ethereum migrated from PoW to PoS by increasing transaction fees on December 5, 2022.
• Ethereum transitioned from PoW to PoS on September 15, 2022, reducing its energy consumption by about 99.95%.
• Ethereum switched from PoW to PoS by launching a new blockchain on October 1, 2022.

15. What is the block creation process in Ethereum`s PoS?

• Validators create blocks, with one validator randomly selected every 12 seconds to be the block proposer.
• A single miner generates a block every 10 seconds in a competitive manner.
• Miners must solve complex puzzles to propose new blocks every minute.
• Nodes write transactions directly into the blockchain without a selection process.

16. How are blocks produced in Ethereum`s PoS?

• The block producer drafts a block and sends it for approval by miners.
• The block proposer creates transactions manually and submits them.
• The block proposer requests a bundle of transactions as an `execution payload`.
• The block creator mines a new block through competitive computing.

17. What is the reward for block production in Ethereum`s PoS?

• The block production is rewarded in BTC.
• The block production is rewarded in ETH.
• The block production is rewarded in USD.
• The block production is rewarded in LTC.

18. How does Ethereum handle rare cases of multiple possible blocks?

• The network selects the block with the most transactions processed first.
• Random selection is used to choose any block without considering weight.
• In rare cases, the fork-choice algorithm picks the block that forms the chain with the greatest weight of attestations.
• The last block mined is always chosen regardless of weight.

19. What is the chain selection rule in Ethereum?

• The chain selection rule establishes the transaction fee system in Ethereum.
• The chain selection rule defines how miners compete to create new blocks.
• The chain selection rule measures the `weight` of the blockchain based on validator votes.
• The chain selection rule governs the number of transactions per second.

20. How does Ethereum`s PoS reduce energy consumption?

• By requiring each node to validate every block individually.
• By allowing miners to work together to share resources.
• By increasing the number of transactions processed simultaneously.
• By eliminating the need for miners to solve complex computations.

21. What is Gasper in Ethereum?

• Gasper is a blockchain protocol primarily for digital identity verification.
• Gasper is a consensus mechanism that combines Casper FFG proof-of-stake with the GHOST fork-choice rule.
• Gasper is a decentralized application built on the Ethereum platform.
• Gasper is a type of cryptocurrency wallet used for Ethereum transactions.

22. What is the main advantage of Ethereum`s transition to PoS?

• Faster block confirmation times only.
• Unlimited supply of Ethereum tokens.
• Increased transaction fees and costs.
• Significant reduction in energy consumption.

23. How has Ethereum`s block time changed with PoS?

• Ethereum`s block time has increased to 20 seconds.
• Ethereum`s block time has decreased to 5 seconds.
• Ethereum`s block time remains variable without changes.
• Ethereum`s block time has become more consistent at 12 seconds.

24. How has Ethereum`s scalability changed with PoS?

• Ethereum`s scalability has drastically increased due to a higher block size limit.
• Ethereum`s scalability has improved slightly due to consistent block times and unchanged block sizes.
• Ethereum`s scalability has remained the same with no changes in throughput.
• Ethereum`s scalability has worsened because of slower transaction speeds.

25. What is the role of validators in Ethereum`s PoS?

• Validators compete with each other to mine blocks and earn transaction fees.
• Validators approve transactions by eliminating fraudulent ones for network safety.
• Validators create blocks and are rewarded in ETH for their participation in validating transactions.
• Validators maintain the network by managing user accounts and keeping records.

26. How does Ethereum`s PoS ensure network security?

• Ethereum`s PoS secures the network by allowing anyone to submit transactions without validation.
• Ethereum`s PoS ensures network security by making it costly to attack the network, as a large amount of staked ether is required to manipulate the chain.
• Ethereum`s PoS guarantees security by randomly choosing validators without any stake requirement.
• Ethereum`s PoS enhances security by restricting access to nodes that lack sufficient hardware.

27. What is the difference in block creation between PoW and PoS?

• In PoW, validators are randomly selected to create blocks, while in PoS, miners compete to create blocks.
• In PoW, miners compete to create blocks, while in PoS, validators are randomly selected to create blocks.
• In PoW, blocks are created every 12 seconds, while in PoS, they are created based on network efficiency.
• In PoW, blocks are created continuously, while in PoS, they are created only in peak usage times.

28. How does Ethereum`s PoS handle conflicts between blocks?

• Ethereum`s PoS requires a majority of miners to agree on the block before proceeding.
• Ethereum`s PoS picks the first block that arrives in the network, ignoring all others.
• Ethereum`s PoS uses a fork-choice algorithm to select the `heaviest` chain based on validator votes and their staked ether.
• Ethereum`s PoS randomly selects blocks from all incoming transactions without any rules.

29. What is the role of the fork-choice rule in Ethereum`s PoS?

• The fork-choice rule selects the block that forms the chain with the greatest weight of attestations.
• The fork-choice rule is responsible for randomly selecting a block proposer.
• The fork-choice rule determines the fastest block to be added to the chain.
• The fork-choice rule counts the number of transactions in each block.

30. How does Ethereum`s PoS reduce computational power usage?

• By increasing the number of transactions processed per second.
• By allowing any node to validate transactions without staking.
• By eliminating the need for miners to use vast computational resources.
• By using advanced hardware to boost mining efficiency.