Comprehensive Blockchain Technology and
Application Overview for Students Exam
UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
What is blockchain? - CORRECT ANSWER A distributed database of immutable records
called blocks, secured with cryptography and linked together to form a public ledger.
What does immutability in blockchain mean? - CORRECT ANSWER Once data is recorded in
a block, it cannot be altered.
What is decentralization in blockchain? - CORRECT ANSWER No central authority; every
participant holds a copy of the ledger.
What is the role of cryptographic primitives in blockchain? - CORRECT ANSWER They
include public-private keys, hash functions, and digital signatures that secure transactions.
What is a public key? - CORRECT ANSWER Acts like an email address that anyone can use to
send funds; shared openly.
What is a private key? - CORRECT ANSWER A secret password used to sign transactions;
kept confidential.
What is a hash function? - CORRECT ANSWER Converts input data into a fixed-size
alphanumeric string; it is one-way and deterministic.
What hash function does Bitcoin use? - CORRECT ANSWER SHA-256, which outputs a 64-
character (256-bit) hash.
What is a digital signature? - CORRECT ANSWER A transaction signed with the sender's
private key, allowing verification with the sender's public key.
,What are the components of a block structure? - CORRECT ANSWER Previous Hash,
Transactions, Nonce, Block Hash.
What is the purpose of the nonce in blockchain? - CORRECT ANSWER A random number
miners adjust to satisfy the proof-of-work target.
What happens during the transaction initiation phase? - CORRECT ANSWER The sender
includes the amount, sender's and receiver's wallet addresses, and signs with their private key.
What is the mining process in blockchain? - CORRECT ANSWER Miners solve the proof-of-
work puzzle; the winning miner adds the block to the chain and receives a block reward.
What is the reward halving in Bitcoin? - CORRECT ANSWER The initial reward halves
approximately every four years.
How does blockchain enhance voting? - CORRECT ANSWER By providing enhanced
transparency and tamper-resistance.
What is a smart contract? - CORRECT ANSWER Self-executing code stored on the blockchain
that automatically enforces agreements when conditions are met.
What is the difference between Bitcoin and Ethereum? - CORRECT ANSWER Bitcoin focuses
on peer-to-peer value transfer; Ethereum supports decentralized applications via smart contracts.
What is the significance of the Merkle root? - CORRECT ANSWER It is the hash of all
transactions built via a Merkle tree, ensuring data integrity in a block.
What are the limitations of traditional banking? - CORRECT ANSWER Centralized control,
high fees, limited availability, and security risks.
How does blockchain improve transaction costs? - CORRECT ANSWER By eliminating
intermediaries, which reduces fees.
, What is the avalanche effect in hashing? - CORRECT ANSWER Small modifications to input
data result in drastically different hash outputs.
What is the target in mining? - CORRECT ANSWER A difficulty threshold that the resulting
hash must be lower than.
What does proof-of-work (PoW) require from miners? - CORRECT ANSWER To find a nonce
such that the block hash is below the network's target.
What is the genesis block? - CORRECT ANSWER The first block in a blockchain, which has a
previous hash of 0.
What is the role of miners in blockchain? - CORRECT ANSWER To validate transactions,
bundle them into blocks, and add them to the blockchain.
What is the purpose of the block hash? - CORRECT ANSWER It serves as the digital signature
of the block's contents.
What is the significance of the timestamp in a block? - CORRECT ANSWER It records the
Unix time when the block was mined.
What is the importance of transparency in blockchain? - CORRECT ANSWER All transactions
are visible to network participants, enhancing trust.
What is a consensus mechanism? - CORRECT ANSWER A protocol that ensures all nodes
agree on the state of the blockchain.
What is a nonce in blockchain? - CORRECT ANSWER A nonce is a number used once in
cryptographic communication, crucial for mining and validating blocks.
What is the primary function of a miner in a blockchain network? - CORRECT ANSWER To
present a valid hash and broadcast the solution for validation by the network.
Application Overview for Students Exam
UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
What is blockchain? - CORRECT ANSWER A distributed database of immutable records
called blocks, secured with cryptography and linked together to form a public ledger.
What does immutability in blockchain mean? - CORRECT ANSWER Once data is recorded in
a block, it cannot be altered.
What is decentralization in blockchain? - CORRECT ANSWER No central authority; every
participant holds a copy of the ledger.
What is the role of cryptographic primitives in blockchain? - CORRECT ANSWER They
include public-private keys, hash functions, and digital signatures that secure transactions.
What is a public key? - CORRECT ANSWER Acts like an email address that anyone can use to
send funds; shared openly.
What is a private key? - CORRECT ANSWER A secret password used to sign transactions;
kept confidential.
What is a hash function? - CORRECT ANSWER Converts input data into a fixed-size
alphanumeric string; it is one-way and deterministic.
What hash function does Bitcoin use? - CORRECT ANSWER SHA-256, which outputs a 64-
character (256-bit) hash.
What is a digital signature? - CORRECT ANSWER A transaction signed with the sender's
private key, allowing verification with the sender's public key.
,What are the components of a block structure? - CORRECT ANSWER Previous Hash,
Transactions, Nonce, Block Hash.
What is the purpose of the nonce in blockchain? - CORRECT ANSWER A random number
miners adjust to satisfy the proof-of-work target.
What happens during the transaction initiation phase? - CORRECT ANSWER The sender
includes the amount, sender's and receiver's wallet addresses, and signs with their private key.
What is the mining process in blockchain? - CORRECT ANSWER Miners solve the proof-of-
work puzzle; the winning miner adds the block to the chain and receives a block reward.
What is the reward halving in Bitcoin? - CORRECT ANSWER The initial reward halves
approximately every four years.
How does blockchain enhance voting? - CORRECT ANSWER By providing enhanced
transparency and tamper-resistance.
What is a smart contract? - CORRECT ANSWER Self-executing code stored on the blockchain
that automatically enforces agreements when conditions are met.
What is the difference between Bitcoin and Ethereum? - CORRECT ANSWER Bitcoin focuses
on peer-to-peer value transfer; Ethereum supports decentralized applications via smart contracts.
What is the significance of the Merkle root? - CORRECT ANSWER It is the hash of all
transactions built via a Merkle tree, ensuring data integrity in a block.
What are the limitations of traditional banking? - CORRECT ANSWER Centralized control,
high fees, limited availability, and security risks.
How does blockchain improve transaction costs? - CORRECT ANSWER By eliminating
intermediaries, which reduces fees.
, What is the avalanche effect in hashing? - CORRECT ANSWER Small modifications to input
data result in drastically different hash outputs.
What is the target in mining? - CORRECT ANSWER A difficulty threshold that the resulting
hash must be lower than.
What does proof-of-work (PoW) require from miners? - CORRECT ANSWER To find a nonce
such that the block hash is below the network's target.
What is the genesis block? - CORRECT ANSWER The first block in a blockchain, which has a
previous hash of 0.
What is the role of miners in blockchain? - CORRECT ANSWER To validate transactions,
bundle them into blocks, and add them to the blockchain.
What is the purpose of the block hash? - CORRECT ANSWER It serves as the digital signature
of the block's contents.
What is the significance of the timestamp in a block? - CORRECT ANSWER It records the
Unix time when the block was mined.
What is the importance of transparency in blockchain? - CORRECT ANSWER All transactions
are visible to network participants, enhancing trust.
What is a consensus mechanism? - CORRECT ANSWER A protocol that ensures all nodes
agree on the state of the blockchain.
What is a nonce in blockchain? - CORRECT ANSWER A nonce is a number used once in
cryptographic communication, crucial for mining and validating blocks.
What is the primary function of a miner in a blockchain network? - CORRECT ANSWER To
present a valid hash and broadcast the solution for validation by the network.
