Guide: Learn Blockchain

Practical Exercises

Inspect block 500000 in any blockchain explorer to answer question (1) to (3).

The following are questions specific to block #500000

1. What is the number of transactions in this block?

2. What is the sum of block reward and fee reward?

   Block Reward BTC: Fee Reward BTC: Sum (Total BTC):

3. Inspect the miner responsible for block #500000. In the coinbase transaction of this block, how many bitcoins are transferred and to whom? Paste the full address into the answer field. Do not perform any rounding to the transaction amount.

   Output Address:Output Amount BTC:
The following are general questions relating to the Bitcoin protocol

4. What is the hashMerkleRoot field referring to in Bitcoin mining?

   The 256-bit hash of the previous block header

   The 256-bit hash of the Merkle root of the block's transactions

   The 256-bit hash of the current block header along with the previous Merkle root

   The 256-bit hash of the difficulty target to produce a valid Merkle root

5. Supposed the miner has exhausted all possible bits of the nonce, what can be done to reset the nonce and try again?
   Pick all that apply.

   Increment extraNonce in the coinbase transactionIncrement nTime in the block headerDecrement nBits in the block headerIncrement nBits to reduce the difficulty for finding a qualifying nonce

6. When an accidental fork occur from two or more miners finding a block within seconds of each other, how is this fork resolved?

   All transactions from forks are considered orphaned blocks and added to the mempool for inclusion again

   Nonce is incremented for every block and the miner will try again with a higher difficulty target, in the hopes of resolving a fork

   Wait for subsequent blocks to be mined, so one chain becomes longer than the other(s) and the network abandons the blocks not in the longest chain

7. What is the search space for the nonce?

   The range of values from 0 to 2^32

   The range of values from 0 to 2^64

   The range of values from 0 up to the number of transactions in the block

   There is no search space, the nonce is incremented indefinitely until a hash that meets the difficulty target is found