Consensus and Mining

Question 1

Four ingredients of Bitcoin’s emergent consensus?

Answer 1

TX check → Block make → Block check → Chain pick (longest‑work).

Question 2

Proof‑of‑Work definition?

Answer 2

Nonce search so block hash < difficulty target; costly to find, easy to verify.

Question 3

Why does difficulty retarget every 2016 blocks?

Answer 3

Keeps average block interval ~10 minutes regardless of total hash‑power.

Question 4

Next block subsidy after the 2024 halving?

Answer 4

3.125 BTC per block.

Question 5

‘6 confirmations’ rule means?

Answer 5

Wait for 6 subsequent blocks before treating a payment as irreversible.

Question 6

Fork resolution rule?

Answer 6

Nodes always follow the longest‑work chain; shorter branches are orphaned.

Question 7

Hash‑power majority risk?

Answer 7

Controlling >50 % could censor or double‑spend; decentralised mining mitigates.

Question 8

Purpose of a mining pool?

Answer 8

Aggregate miners’ hash‑power and split rewards for steadier earnings.

Question 9

Two parts of a miner’s income?

Answer 9

Block subsidy + transaction fees.

Question 10

Mnemonic for pre‑block txn validation?

Answer 10

“UTXO → Sig → Fee” (unspent, properly signed, fee‑valid).