Blockchain

What is the role of a timestamp in a blockchain block? a) To record when the block was added to the blockchain b) To encrypt the transactions in the block c) To identify the size of the block d) To reward the miners for their work Answer: a) To record when the block was added […]

How does blockchain ensure transparency? a) By keeping all transactions private b) By making the ledger accessible to all participants c) By encrypting all data d) By only allowing governments to access the ledger Answer: b) By making the ledger accessible to all participants Explanation: Blockchain ensures transparency by making the distributed ledger available to

What is a blockchain explorer? a) A tool used to view information about blockchain transactions and blocks b) A miner that validates transactions c) A program that manages wallets d) A type of cryptocurrency wallet Answer: a) A tool used to view information about blockchain transactions and blocks Explanation: A blockchain explorer is a web-based

What is gas in the Ethereum blockchain? a) A measure of computational work required for transactions b) A type of cryptocurrency c) A block reward given to miners d) A cryptographic function Answer: a) A measure of computational work required for transactions Explanation: Gas is a unit that measures the computational work required for transactions

What is the double-spending problem in blockchain? a) When a miner solves two blocks at once b) When the same digital currency is spent more than once c) When a blockchain forks into two d) When miners work together to solve a block Answer: b) When the same digital currency is spent more than once

How does blockchain achieve security? a) By encrypting transactions with public and private keys b) By allowing everyone to change the data c) By using centralized servers d) By deleting old blocks regularly Answer: a) By encrypting transactions with public and private keys Explanation: Blockchain achieves security by using cryptographic techniques like public and private

What is a permissioned blockchain? a) A blockchain that is open to the public b) A blockchain that only allows specific participants to validate transactions c) A blockchain without any permissions d) A government-controlled blockchain Answer: b) A blockchain that only allows specific participants to validate transactions Explanation: A permissioned blockchain allows only authorized participants

Which cryptocurrency was the first to implement blockchain technology? a) Ethereum b) Litecoin c) Bitcoin d) Ripple Answer: c) Bitcoin Explanation: Bitcoin was the first cryptocurrency to implement blockchain technology when it was launched in 2009 by an unknown person or group of people using the name Satoshi Nakamoto. Reference: Blockchain Quiz – MCQ Questions

What is “immutability” in blockchain? a) Data can be easily modified b) Data can be deleted if needed c) Once data is recorded on the blockchain, it cannot be changed d) Data can be changed only by miners Answer: c) Once data is recorded on the blockchain, it cannot be changed Explanation: Immutability means that

What is the primary advantage of using blockchain? a) Centralized control of data b) Increased transparency and security c) Lower computational power d) Fewer nodes in the network Answer: b) Increased transparency and security Explanation: Blockchain’s primary advantage is that it increases transparency and security by using decentralized, cryptographically secure data storage. Reference: Blockchain Quiz

What is a “cryptographic hash” in blockchain? a) A mathematical function that converts input into a fixed-length output b) A block that is encrypted with a private key c) A key used to generate blocks d) A program used to mine cryptocurrencies Answer: a) A mathematical function that converts input into a fixed-length output Explanation:

What is a permissionless blockchain? a) A blockchain that requires approval to join b) A blockchain that anyone can join and participate in c) A blockchain used only for private companies d) A blockchain that operates without nodes Answer: b) A blockchain that anyone can join and participate in Explanation: A permissionless blockchain allows anyone

What is a 51% attack in blockchain? a) An attack that disrupts mining b) When a miner or group controls more than 51% of the blockchain’s computational power c) An attack to steal private keys d) A way to fork the blockchain Answer: b) When a miner or group controls more than 51% of the

What is a fork in blockchain? a) A way to delete blocks from the blockchain b) A change or split in the blockchain protocol c) A cryptographic function used to sign transactions d) A security feature to prevent hacking Answer: b) A change or split in the blockchain protocol Explanation: A fork in blockchain refers

What is a node in blockchain? a) A user of a blockchain network b) A device or participant that helps maintain the blockchain c) A cryptographic key d) A type of smart contract Answer: b) A device or participant that helps maintain the blockchain Explanation: A node is a participant in the blockchain network that

Which consensus algorithm does Bitcoin use? a) Proof of Stake (PoS) b) Delegated Proof of Stake (DPoS) c) Proof of Work (PoW) d) Byzantine Fault Tolerance (BFT) Answer: c) Proof of Work (PoW) Explanation: Bitcoin uses Proof of Work (PoW) as its consensus algorithm, which requires miners to solve complex computational puzzles to validate transactions.

What is the genesis block in blockchain? a) The last block of the blockchain b) The first block in the blockchain c) A block that is encrypted for security d) A block that contains only metadata Answer: b) The first block in the blockchain Explanation: The genesis block is the first block of a blockchain,

What is a public key in blockchain? a) A key used to encrypt blockchain data b) A publicly available key used to verify transactions c) A key used to generate new blocks d) A key to unlock smart contracts Answer: b) A publicly available key used to verify transactions Explanation: A public key is shared

What is a private key in blockchain? a) A public identifier for a blockchain wallet b) A secret key used to sign transactions c) A shared password for accessing the blockchain d) A key to encrypt data in blocks Answer: b) A secret key used to sign transactions Explanation: A private key is a cryptographic

What is a “smart contract” in blockchain? a) A self-executing contract with the terms written in code b) A physical contract stored on the blockchain c) A legal agreement between two blockchain users d) A software application that encrypts blockchain data Answer: a) A self-executing contract with the terms written in code Explanation: Smart contracts

What is a consensus algorithm in blockchain? a) An algorithm used to control inflation b) A method to achieve agreement on the state of the blockchain c) A program that encrypts blockchain transactions d) A process to create private keys Answer: b) A method to achieve agreement on the state of the blockchain Explanation: A

What does “decentralized” mean in blockchain? a) All control is with one central authority b) Control is distributed among many participants c) Blockchain is hosted on a single server d) It is a government-controlled network Answer: b) Control is distributed among many participants Explanation: In a decentralized system, control and decision-making are distributed across multiple

What is the role of miners in blockchain? a) To store data on the blockchain b) To verify and validate transactions c) To create new types of cryptocurrencies d) To manage blockchain wallets Answer: b) To verify and validate transactions Explanation: Miners use computational power to verify and validate transactions, adding them to the blockchain

What is a block in a blockchain? a) A group of transactions bundled together b) A type of cryptocurrency c) A single transaction in the blockchain d) A user’s private key Answer: a) A group of transactions bundled together Explanation: A block contains a list of transactions that are verified and recorded in the blockchain,

What is blockchain technology? a) A centralized ledger of transactions b) A decentralized, distributed ledger of transactions c) A physical chain of blocks d) A private database for financial institutions Answer: b) A decentralized, distributed ledger of transactions Explanation: Blockchain is a decentralized and distributed ledger that records transactions across multiple computers, ensuring security and