Cryptocurrency Mining and Transaction Lifecycle 2

Question 1

What happens to a Bitcoin transaction before it is included in a block?

Accepted Answer

It waits in the mempool

Answer

Unconfirmed transactions sit in the mempool (memory pool) until a miner selects and includes them in a block.

Question 2

Which hashing algorithm does Bitcoin's proof-of-work system use?

Accepted Answer

SHA-256

Answer

Bitcoin uses SHA-256 (Secure Hash Algorithm 256-bit) for its proof-of-work mining process.

Question 3

What is a 'stale block' in cryptocurrency mining?

Accepted Answer

A valid block that was mined but not accepted because another block was found first

Answer

A stale block is a correctly solved block that arrives too late because another miner already found and broadcast a valid block at the same height.

Question 4

What does 'transaction throughput' measure in a blockchain network?

Accepted Answer

The number of transactions processed per second (TPS)

Answer

Transaction throughput, measured in TPS (transactions per second), indicates how many transactions a network can process in a given time period.

Question 5

In Bitcoin mining, what is the purpose of the 'nonce'?

Accepted Answer

To vary the block header input so miners can find a valid hash

Answer

The nonce is a 32-bit number that miners increment repeatedly to produce a block hash that meets the network's difficulty target.

Cryptocurrency Practice Test