300+ Top Blockchain MCQ Questions and Answers Quiz

Blockchain Multiple Choice Questions

1. Blockchain can perform user transactions without involving any third-party intermediaries.

  1. With the help of the third party
  2. Without involving any third party
  3. Without involving any owned
  4. Without involving any authenticated

Answer: B Without involving any third party

Explanation: A shared ledger, or blockchain, is a system that allows thousands of computers or servers to maintain a single, secure, and immutable record. Without the necessity of third-party intermediaries, blockchain may conduct user transactions. All that is required to conduct transactions is the possession of a wallet.

2. What does P2P stand for?

  1. Peer to Peer
  2. Product to Product
  3. Password to Password
  4. None of the above

Answer: A Peer to Peer

Explanation: Blockchains’ P2P (Peer to Peer) architecture offers various advantages over typical client-server networks, including increased security.

3. Blockchain has ____ versions.

  1. 2
  2. 3
  3. 4
  4. 5

Answer: B 3

Explanation: Blockchain has three versions. Blockchain 1.0: Currency. Blockchain 2.0: Smart Contracts. Blockchain 3.0: DApps.

4. Who introduced the digital online cryptocurrency known as Bitcoin?

  1. Satoshi Nakamoto
  2. Nick Szabo
  3. Wei Dai
  4. Hal Finney

Answer: A Satoshi Nakamoto

Explanation: On 3 January 2009, Satoshi Nakamoto mined the genesis block of bitcoin (block number 0), which was worth 50 bitcoins and the bitcoin network was formed.

5. Blockchain is a peer-to-peer _____________ distributed ledger technology that makes the records of any digital asset transparent and unchangeable.

  1. Decentralized
  2. Demanding
  3. Secure
  4. Popular

Answer: A Decentralized

Explanation: Blockchain is a peer-to-peer decentralized distributed ledger technology that makes the records of any digital asset transparent and unchangeable and works without involving any third-party intermediary.

6. Blockchain networks are much _____ and deal with no real single point of failure.

  1. Simpler
  2. Easier to scale
  3. Convenient
  4. Faster

Answer: B Easier to scale

Explanation: In comparison to a standard centralized network, a decentralized network has several advantages, including greater system reliability and privacy. Furthermore, such networks are far easier to grow and have no single point of failure.

7. Bitcoin is a cryptocurrency, which is an application of Blockchain.

  1. True
  2. False

Answer: A True

Explanation: Bitcoin is a cryptocurrency that uses Blockchain technology, whereas Blockchain is the underlying technology that powers Bitcoin and is used in a variety of ways.

8. A blockchain enables peer-to-peer transfer of digital currency without any intermediaries such as banks.

  1. False
  2. True

Answer: B True

Explanation: A blockchain allows for peer-to-peer digital currency transfers without the use of middlemen such as banks.

9. Did Blockchain enable a centralized or a decentralized system for the exchange of value?

  1. Decentralized
  2. Centralized
  3. None of the above
  4. Can’t say

Answer: A Decentralized

Explanation: Simply put, blockchain is a decentralized, distributed ledger technology that keeps track of a digital asset’s provenance.

10. What does a block in a Blockchain have?

  1. Header & Digital ledger
  2. Bitcoins & Input
  3. Transactions & Bitcoins
  4. Header & Transaction

Answer: D Header & Transaction

Explanation: The block is made up of a metadata-filled header and a long list of transactions that make up the majority of its size. The typical transaction is at least 250 bytes long, while the average block comprises more than 500 transactions.

11. What does UTXO stand for?

  1. Unspent Trade Offer
  2. Unspent Transaction xeroxed Output
  3. Unique Transaction Offer
  4. Unspent Transaction Output

Answer: D Unspent Transaction Output

Explanation: Unspent Transaction (TX) Output is referred to as UTXO. In a nutshell, it’s the amount of cryptocurrency change left over after each transaction.

12. Does a transaction generate new UTXOs for transferring the amount specified in the input UTXOS?

  1. False
  2. True

Answer: B True

Explanation: A UTXO is the amount of digital cash left over after a bitcoin transaction has been completed.

13. Transaction 0 in every block of the bitcoin blockchain________.

  1. Is for paying the miner fees
  2. Does not have any input UTXO
  3. Is called the coinbase transaction
  4. All of the above

Answer: D All of the above

Explanation: Every block of the bitcoin blockchain has transaction 0 in it. It’s known as the coinbase transaction, and it’s used to pay miner fees because it doesn’t contain any input UTXO.

14. What is the genesis block?

  1. Any block created by the founder
  2. The last block created in the Blockchain
  3. The first block of a Blockchain
  4. The first transaction in each block

Answer: C The first block of a Blockchain

Explanation: Since every bitcoin traces its genealogy back to the Genesis Block, also known as Block 0, every other bitcoin block may trace its lineage back to it.

15. ___ hosts the software needed for transaction initiation, validation, mining, block creation, and smart contract execution.

  1. External Account
  2. EVM
  3. Ethereum full node
  4. Smart Contract

Answer: C Ethereum full node

Explanation: Ethereum is a distributed network of computers (known as nodes) that can validate blocks and transaction data by executing software. To “run” a node on your computer, you’ll need a client application.

16. __________ receive verify, gather and execute transactions.

  1. Miner nodes
  2. Smart Contracts
  3. Light wallets
  4. Ethereum full node

Answer: A Miner nodes

Explanation: On the network, miner nodes receive, aggregate, validate, and execute transactions. They are compensated for their efforts in the blockchain’s native currency, Ether in this example.

17. What is Blockchain?

  1. A currency
  2. A ledger
  3. A type of currency
  4. A distributed ledger on a peer-to-peer network

Answer: D A distributed ledger on a peer-to-peer network

Explanation: A blockchain is a distributed digital ledger that records and replicates transactions in real-time across a network. A blockchain is a growing list of documents, known as blocks, that are cryptographically linked together.

18. Bitcoin is based on _________ blockchain.

  1. Private
  2. Public
  3. Public Permissioned
  4. Permissioned

Answer: B Public

Explanation: Public blockchain can be used to construct a completely open blockchain, similar to Bitcoin, that allows everyone and everyone to join and contribute to the network.

19. BATM stands for _____.

  1. Bounded access transaction machine
  2. Broadcast ATM
  3. Bitcoin ATM
  4. Blockchain ATM

Answer: C Bitcoin ATM

Explanation: A Bitcoin ATM (abbreviated as BATM) is a kiosk where a person can purchase Bitcoin using an automated teller machine.

20. Smart Contract characteristics do not include:

  1. Alterable
  2. Fast and cost-effective
  3. A high degree of accuracy
  4. Transparency

Answer: A Alterable

Explanation: Smart contracts (SC) are digital code sets designed to make asset transfers easier (including non-digital assets). They are clear, precise, quick, and cost-effective.

21. A popular public-private key implementation known as Rivest-Shamir Adelman (RSA) algorithm is used for the Bitcoin and Ethereum Blockchain.

  1. False
  2. True

Answer: A False

Explanation: Bitcoin is a digital currency that is secure thanks to Blockchain technology. Ethereum Blockchain Ethereum uses a blockchain network to perform its operations. Ethereum, a public blockchain network, is increasingly being used to facilitate enterprise transactions needing automatic, rule-based asset transfer, just like all cryptocurrencies.

22. For the simple symmetric key example discussed in the lecture, it is easy to derive the secret key from the encrypted data.

  1. True
  2. False

Answer: A True

Explanation: Symmetric encryption, often known as a secret key algorithm, employs only one key: a secret key for message encryption and decoding. It is simple to deduce the secret key from the encrypted data in the simple symmetric key case described in the lecture.

23. What type of hash is used when there is a fixed number of items to be hashed, such as the items in a block header, and we are verifying the composite block integrity?

  1. Tree-structured Hash
  2. Complex hash
  3. Simple Hash
  4. Either

Answer: C Simple Hash

Explanation: Masking off the bottom m bits to use as an index into a table of size 2 m is a basic hash function. A folding hash code is created by dividing the input into n pieces of m bits each, where 2m is the table size, then combining the sections with a parity-preserving bitwise operation like ADD or XOR.

24. What type of hash function is used, when there is a variable number of items to be hashed, such as the many state changes in a block?

  1. Complex hash
  2. Simple Hash
  3. Tree-structured Hash
  4. Either

Answer: C Tree-structured Hash

Explanation: In the fields of cryptography and computing science, Hash trees, also known as Merkle trees, are a sort of data structure that stores a tree of summary information about a bigger piece of data, such as a file, and is used to validate its contents. Hash trees are a subset of hash lists, which are themselves subsets of hashing.

25. The transaction Merkle Tree root value in a Bitcoin block is calculated using,

  1. Hash of transactions
  2. Previous block’s hash
  3. Number of transactions
  4. None of the above

Answer: A Hash of transactions

Explanation: By hashing together pairs of TXIDs, a Merkle root is generated, which gives you a brief yet unique fingerprint for all the transactions in a block.

26. What is a DApp?

  1. A type of cryptocurrency
  2. A condiment
  3. A type of blockchain
  4. A decentralized application

Answer: D A decentralized application

Explanation: A decentralized application, often known as a Dapp, is a software program that runs on a distributed network. It’s run on a peer-to-peer platform rather than a centralized server.

27. Hash identifying each block in the blockchain is generated using which of the following cryptographic algorithm?

  1. SHA128
  2. SHA256
  3. Both of them
  4. None of them

Answer: B SHA256

Explanation: SHA 256 is a member of the SHA 2 algorithm family, with SHA standing for Secure Hash Algorithm. It was a joint effort between the National Security Agency and the National Institute of Standards and Technology to introduce a successor to the SHA 1 family, which was slowly losing power against brute force attacks. It was published in 2001.

28. How often does the Bitcoin ledger reconcile?

  1. Every day
  2. Every 3 months
  3. Every 3 minutes
  4. Every 10 minutes

Answer: B Every 3 months

Explanation: General ledger reconciliations should be performed at least once a quarter to catch errors in transaction amounts and categories. Technology is not impervious to errors.

29. Which is/are the applications of Blockchain?

  1. Cross-border payments
  2. Anti-money laundering tracking system
  3. Supply chain and logistics monitoring
  4. All the above

Answer: D All the above

Explanation: Cross-border payments, anti-money laundering tracking systems, supply chain and logistics monitoring, and so on are just a few of the possibilities for blockchain.

30. What is a smart contract?

  1. Programs stored on a blockchain that run when predetermined conditions are met
  2. Online contract
  3. Digital contract
  4. All the above

Answer: A Programs stored on a blockchain that run when predetermined conditions are met

Explanation: A “smart contract” is software that runs on Ethereum’s blockchain. It’s a collection of code (its functions) and data (its state) that lives on the Ethereum blockchain at a single address. Ethereum accounts come in the form of smart contracts.

31. Bitcoin is a solution to the double-spend problem?

  1. True
  2. False
  3. Sometimes
  4. None of the above

Answer: A True

Explanation: Bitcoin solves the problem of double-spending with the help of nonce.

32. Blockchain is a ______ ?

  1. Push technology
  2. Pull technology
  3. Both push and pull technology
  4. None of the above

Answer: A Push technology

Explanation: A push-based settlement system is how blockchain technology works. This implies that the person has control over the resource they want to verify on the blockchain. This might include things like bitcoin, certificate validation, and land titles, among other things.

33. What is a miner?

  1. A type of blockchain
  2. An algorithm that predicts the next part of the chain
  3. A person doing calculations to verify a transaction
  4. Computers that validate and process blockchain transactions

Answer: D Computers that validate and process blockchain transactions

Explanation: Miners are accountants who keep track of all transactions on the blockchain. The idea is simple: if you want your payment to be valid, you need proof of payment. The miners are in charge of keeping track of your payment.

34. Where is a Blockchain’s central server?

  1. Where the blockchain is created
  2. Located with the owner of the server
  3. There is no central server, it is distributed
  4. Ordered Node

Answer: C There is no central server, it is distributed

Explanation: There is no central server in a blockchain, which is a digital distributed ledger of transactions that are recorded and duplicated in real-time throughout a network.

35. Transactions per second (TPS) for Proof-of-Work Blockchain are approximate?

  1. 24K per second
  2. 175K per second
  3. Only limited to the number of nodes on the network
  4. 7-15 per second

Answer: D 7-15 per second

36. The height of the block is the ____ in the chain between it and the genesis block.

  1. Metadata that is
  2. Number of blocks
  3. Merkle tree hash
  4. Size of the memory cache

Answer: B Number of blocks

Explanation: The total number of blocks connected since the genesis block is the block height. The number of blocks between any given block and the genesis block determines its height.

37. Which of the following problems did Blockchain solve for cryptocurrencies?

  1. Anonymity
  2. Double Spending
  3. Destination of currencies
  4. None of the above

Answer: B Double Spending

Explanation: Blockchain solved the problem of double-spending for cryptocurrencies using a nonce.

38. Blockchain does not provide?

  1. Security
  2. Immutability
  3. Fault tolerance
  4. Fast transaction time

Answer: D Fast transaction time

Explanation: When a blockchain’s scalability is high, it means the network can handle a large number of transactions quickly. It enables separate accounts to exchange data swiftly, if not immediately, independent of the network traffic.

39. A contract in size is restricted to,

  1. 24576 Bytes
  2. 1 Kilo Bytes
  3. 23575 Bytes
  4. No limit

Answer: A 24576 Bytes

40. What is the purpose of a Nonce?

  1. Follows nouns
  2. A Hash Function
  3. Prevents Double Spending
  4. Send Information to the Blockchain Network

Answer: C Prevents Double Spending

Explanation: Every account has a globally available nonce that protects against same-chain replay attacks and double spending. The nonce is the transaction’s sequence number, which miners examine since a block with an erroneous nonce is invalid.

41. What is cold storage?

  1. A place to Hang your Coat
  2. A private key connected to the internet
  3. A private key not connected to the internet
  4. A desktop wallet

Answer: B A private key connected to the internet

Explanation: The phrase “cold storage” usually refers to the part of the global supply chain that stores products and materials that need to be kept at a specific temperature.

42. What powers the Ethereum Virtual Machine?

  1. Gas
  2. Ether
  3. Bitcoin
  4. Block Rewards

Answer: A Gas

Explanation: In the Ethereum Virtual Machine ology, ether is the gas that drives the EVM’s operations. Gas is a unit of measure for how much computational labor is necessary to perform transactions and smart contracts.

43. What is Proof of Stake?

  1. A certificate needed to use the blockchain
  2. A password needed to access an exchange
  3. How private keys are made
  4. A transaction and Block Verification Protocol

Answer: D A transaction and Block Verification Protocol

Explanation: According to the Proof of Stake (PoS) idea, a person’s ability to mine or validate block transactions is proportional to the number of coins they own. This means that the more coins a miner owns, the greater their mining power.

44. What is Not a Ledger type considered by users in Blockchain?

  1. Distributed Ledger
  2. Decentralized Ledger
  3. Both A and B
  4. None of these

Answer: D None of these

Explanation: There are primarily three sorts of ledgers: sales, purchase, and general ledger.

45. What are mechanisms that allow tokens and other digital assets from one blockchain to be securely used in a separate blockchain called?

  1. Parachains
  2. Blockbabies
  3. Sidechains
  4. Altchains

Answer: A Parachains

Explanation: A sidechain is a blockchain that runs in parallel to the Ethereum mainnet and is self-contained. It has its algorithm for reaching a consensus.

46. If a hacker wanted to alter a blockchain, what percentage of the block copies would he have to alter?

  1. Only his copy
  2. 1%
  3. 51%
  4. 100%

Answer: C 51%

Explanation: If a hacker intended to change a blockchain, he’d only be able to block 51% of block copies.

47. What biblical name is given to the first block in blockchain?

  1. Primal
  2. Origin
  3. Genesis
  4. Ada

Answer: C Genesis

Explanation: A genesis block (block number 0) is the initial block in a blockchain. This is the sole block in a blockchain that does not include any transactions and does not have a valid reference to a previous block.

48. Bitcoin is created by ______.

  1. Saifedean Ammius
  2. Satoshi Nakamoto
  3. Vitalik Buterin
  4. None of these

Answer: B Satoshi Nakamoto

Explanation: Satoshi Nakamoto is the anonymous Bitcoin founder who authored the Bitcoin Protocol’s original code.

49. Decentralized blockchains are immutable?

  1. True
  2. False
  3. Can be true or false
  4. Cannot say

Answer: A True

Explanation: True, Decentralized blockchains are immutable, which means that the data entered is irreversible. For Bitcoin, this means that transactions are permanently recorded and viewable to anyone.

50. A blockchain is a type of?

  1. Object
  2. Database
  3. Table
  4. View

Answer: B Database

Explanation: Blockchain is a specific type of database.

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