CBP Blockchain and Transaction Mechanics 2

Question 1

What is the purpose of the nLockTime field in a Bitcoin transaction?

Accepted Answer

It specifies the earliest block height or timestamp at which the transaction can be mined

Answer

It sets the maximum fee a transaction will pay

Answer

It locks the UTXO for a specific public key

Answer

It determines the minimum number of confirmations required

Question 2

In a Bitcoin transaction, what does the sequence number field on each input control when nLockTime is used?

Accepted Answer

Whether the input opts into RBF (Replace-By-Fee)

Answer

The order inputs are signed

Answer

The number of signatures required

Answer

The fee priority of the transaction

Question 3

What is the maximum size of a standard Bitcoin block introduced by the SegWit upgrade (in weight units)?

Accepted Answer

4,000,000 weight units

Answer

1,000,000 weight units

Answer

2,000,000 weight units

Answer

8,000,000 weight units

Question 4

Which hashing algorithm does Bitcoin use to produce a block's Proof-of-Work?

Accepted Answer

SHA-256 applied twice (double-SHA-256)

Answer

SHA-3

Answer

RIPEMD-160

Answer

Scrypt

Question 5

What information is stored in the coinbase transaction of a Bitcoin block?

Accepted Answer

The block reward plus fees, and an arbitrary data field (up to 100 bytes)

Answer

The miner's private key

Answer

A reference to all previous block headers

Answer

The Merkle root of all UTXOs

Question 6

What does UTXO stand for in Bitcoin's transaction model?

Accepted Answer

Unspent Transaction Output

Answer

Unverified Transaction Exchange Output

Answer

Unified Token Exchange Order

Answer

Unsigned Transaction eXecution Object

Question 7

If a Bitcoin transaction consumes 3 inputs totaling 1.5 BTC and creates 2 outputs totaling 1.48 BTC, what happens to the remaining 0.02 BTC?

Accepted Answer

It is collected by the miner as a transaction fee

Answer

It is returned to the sender automatically

Answer

It is burned and permanently removed from circulation

Answer

It rolls over to the next transaction