Cryptocurrency Mining and Transaction Lifecycle Questions and Answers

Question 1

Which of the following best describes the function of a node's 'mempool' in a blockchain network?

Accepted Answer

A temporary storage area for unconfirmed, but valid, transactions waiting to be included in a block.

Answer

A database of all previously confirmed transactions in the blockchain.

Answer

The cryptographic pool of random nonces used by miners during the hashing process.

Answer

A list of all active mining nodes currently competing to solve the next block.

Question 2

In a Proof-of-Work system like Bitcoin, what is the primary purpose of the 'difficulty adjustment'?

Accepted Answer

To ensure that new blocks are found at a relatively consistent and predictable rate, regardless of changes in total network hash power.

Answer

To increase the total supply of the cryptocurrency over time.

Answer

To assign a ranking to miners based on their processing power.

Answer

To decrease the transaction fees required for inclusion in a block.

Question 3

A miner is constructing a new block for a Proof-of-Work blockchain. They have selected a set of transactions from their mempool. What critical piece of information from the *previous* block must they include in the new block's header to ensure the chain remains unbroken?

Accepted Answer

The hash of the previous block's header.

Answer

The total value of all transactions from the previous block.

Answer

A complete list of all transaction IDs from the previous block.

Answer

The public key of the miner who solved the previous block.

Question 4

An exchange requires 6 confirmations before a user's Bitcoin deposit is considered final. What does '6 confirmations' signify in this context?

Accepted Answer

The transaction has been included in a block, and 5 subsequent blocks have been mined and added to the chain after it.

Answer

The transaction has been validated by 6 different supernodes.

Answer

The user's wallet has re-broadcast the transaction 6 times to ensure propagation.

Answer

The transaction was included in block number 6 of the blockchain.

Question 5

What is the first step in the lifecycle of a typical cryptocurrency transaction after it has been signed by the user's wallet?

Accepted Answer

It is broadcast to the network to be included in other nodes' mempools.

Answer

It is immediately included in a new block by a miner.

Answer

It is sent directly to a centralized server for validation.

Answer

It is queued locally until the next difficulty adjustment period.

Question 6

Which of the following accurately describes a 'stale block,' often colloquially referred to as an 'orphan block'?

Accepted Answer

A valid block that is not accepted into the main blockchain because a competing block at the same height was accepted first.

Answer

A block that contains no transactions and only the coinbase transaction.

Answer

A block that has been intentionally invalidated by a 51% attack.

Answer

A block mined by a node that is not connected to the main network.