Blockchain and Crypto Blockchain Fundamentals & Architecture 2

Question 1

What is a blockchain 'fork' and when does it occur?

Accepted Answer

A split in the blockchain that creates two divergent chains following a rule change or disagreement

Answer

A backup copy of the blockchain stored on an alternate server

Answer

A transaction that is rejected by the majority of nodes

Answer

A scheduled network upgrade that temporarily halts block production

Question 2

Which type of blockchain allows anyone to join, read, and submit transactions without requiring permission?

Accepted Answer

Public blockchain

Answer

Private blockchain

Answer

Consortium blockchain

Answer

Permissioned blockchain

Question 3

Which of the following best defines a smart contract?

Accepted Answer

Self-executing code stored on the blockchain that automatically enforces terms when conditions are met

Answer

A legally binding digital agreement notarized on the blockchain

Answer

A signed contract between two miners governing block reward sharing

Answer

A consensus mechanism used by permissioned blockchains

Question 4

In a Proof of Stake consensus mechanism, what primarily determines a validator's probability of being selected to create the next block?

Accepted Answer

The amount of cryptocurrency the validator has locked up as stake

Answer

The computational hash rate the validator contributes

Answer

The number of blocks the validator has previously produced

Answer

The geographic location and uptime of the validator's node

Question 5

What does the Byzantine Generals Problem describe in distributed computing?

Accepted Answer

The challenge of achieving reliable consensus when some participants may be faulty or malicious

Answer

A cryptographic weakness discovered in Byzantine-era cipher systems

Answer

A routing inefficiency in large peer-to-peer networks

Answer

A denial-of-service vulnerability affecting Byzantine fault-tolerant blockchains

Question 6

What is 'sharding' as a blockchain scalability solution?

Accepted Answer

Partitioning the blockchain into smaller segments that process transactions in parallel

Answer

Splitting a private key into multiple pieces for distributed custody

Answer

Distributing block rewards across multiple mining pools simultaneously

Answer

Creating independent backup copies of the blockchain across data centers

Question 7

What is the 'double-spend problem' that blockchain technology is designed to prevent?

Accepted Answer

Attempting to use the same unit of digital currency in two separate transactions simultaneously

Answer

The risk of a miner collecting block rewards from two different pools

Answer

The overhead cost incurred when processing a transaction across two chains

Answer

The scenario where a user accidentally sends twice the intended amount