FREE Cryptocurrency Blockchain Technology Fundamentals Questions and Answers

Question 1

A development team is launching a new cryptocurrency designed to minimize energy consumption. Instead of requiring intensive computational work, the protocol selects validators to create new blocks based on the amount of currency they have staked as collateral. Which consensus mechanism does this describe?

Accepted Answer

Proof-of-Stake (PoS)

Answer

Proof-of-Stake (PoS) is a consensus mechanism that selects validators based on the quantity of the native currency they hold and are willing to 'stake' or lock up as collateral. This method is significantly more energy-efficient than Proof-of-Work (PoW), which relies on computational power to solve complex puzzles.

Question 2

Within a standard blockchain block header, what is the data structure that is created by recursively hashing pairs of transaction IDs together to efficiently summarize and verify the integrity of all transactions in the block?

Accepted Answer

Merkle Root

Answer

The Merkle Root is a single hash that represents the root of a Merkle tree, which is constructed by hashing all transaction IDs in a block. This structure allows for efficient verification of transactions without needing to download and process the entire block's transaction data.

Question 3

Which of the following is a primary characteristic that distinguishes a private or permissioned blockchain from a public blockchain like Bitcoin?

Accepted Answer

The requirement for participants to be vetted and granted access.

Answer

The core difference between public and private blockchains is access control. Public blockchains are 'permissionless,' allowing anyone to join. Private blockchains are 'permissioned,' meaning participants must be invited and authorized by a central administrator or consortium. The other options are fundamental characteristics of most blockchains, both public and private.

Question 4

What is the fundamental purpose of a smart contract on a blockchain?

Accepted Answer

To act as a self-executing agreement with predefined rules.

Answer

A smart contract is a program stored on a blockchain that automatically executes the terms of an agreement when predefined conditions are met. This removes the need for a traditional intermediary, automating workflows and ensuring outcomes are carried out as programmed.

Question 5

A user controls a single Unspent Transaction Output (UTXO) worth 5 ETH. They initiate a transaction to send 1 ETH to a friend. In a UTXO-based blockchain, how is this transaction typically processed?

Accepted Answer

The original 5 ETH UTXO is consumed, and two new UTXOs are created: one for 1 ETH to the friend and one for approximately 4 ETH back to the sender as change.

Answer

In the UTXO model, transaction inputs are consumed in their entirety. The original 5 ETH UTXO is spent, and the transaction creates new outputs: one for the recipient (1 ETH) and a 'change' output (the remainder, minus transaction fees) that is sent back to the original user under their control.

Cryptocurrency Practice Test

Cryptocurrency Practice Test

FREE Cryptocurrency Blockchain Technology Fundamentals Questions and Answers