Blockchain Eth Flashcards
What is the purpose of blockchain technology? a) Storing data on centralized servers b) Distributed ledger system c) Storing data in JSON format d) None of the above
b) Distributed ledger system
What type of attack involves manipulating the state of a smart contract by exploiting vulnerable functions? a) Phishing b) Reentrancy c) Cross-site scripting d) SQL injection
b) Reentrancy
What is the smallest unit of Ether in Ethereum? a) Gwei b) Wei c) Mega-ether d) Milli-ether
b) Wei
Which blockchain validation mechanism does Ethereum use? a) Proof-of-Work b) Proof-of-Stake c) Proof-of-Authority d) Proof-of-Storage
b) Proof-of-Stake
What is the main disadvantage of Proof-of-Work in blockchain? a) Too much centralized control b) High energy consumption c) Low security d) High transaction fees
b) High energy consumption
Which Ethereum feature helps to estimate the cost of transactions? a) Ether b) Gas c) Proof-of-Stake d) Transaction validator
b) Gas
What does ‘Gas’ in Ethereum refer to? a) Amount of computational work for a transaction b) Storage cost for Ethereum coins c) Proof-of-stake contribution d) Reward for miners
a) Amount of computational work for a transaction
What happens if you specify too low of a gas price for your Ethereum transaction? a) Your transaction will be processed first b) Your transaction might be ignored c) Your transaction will fail and return funds d) Your gas limit will automatically increase
b) Your transaction might be ignored
What is the purpose of using a smart contract on Ethereum? a) To process decentralized applications (dApps) b) To store large files c) To process cryptocurrency transactions only d) To provide centralized control over operations
a) To process decentralized applications (dApps)
What was the major issue with the 2016 Ethereum DAO hack? a) The attacker exploited a bug in a smart contract b) The attacker gained access to private keys c) A bug in Ethereum’s consensus mechanism d) Malicious miners altered transactions
a) The attacker exploited a bug in a smart contract
What language is commonly used to write Ethereum smart contracts? a) JavaScript b) Solidity c) Python d) Java
b) Solidity
Which tool is commonly used for deploying smart contracts in Ethereum? a) Remix b) Truffle c) Hardhat d) All of the above
d) All of the above
What is the transaction cost in Ethereum known as? a) Gas b) Ether c) Wei d) Bitcoin
a) Gas
What is the purpose of the Proof-of-Work algorithm in blockchain? a) To increase the speed of transactions b) To secure the network by solving computational problems c) To validate transactions by users d) To store the blockchain data in nodes
b) To secure the network by solving computational problems
Which is a main advantage of Proof-of-Stake over Proof-of-Work? a) Lower energy consumption b) Faster block generation c) Lower transaction fees d) More decentralization
a) Lower energy consumption
What Ethereum upgrade transitioned the system from Proof-of-Work to Proof-of-Stake? a) ETH2 b) Sharding c) Gas Limit d) Beacon Chain
a) ETH2
What is the key difference between Proof-of-Stake and Proof-of-Work in terms of validation? a) Proof-of-Stake uses computational power, Proof-of-Work uses financial resources b) Proof-of-Stake requires ownership of cryptocurrency to validate transactions, Proof-of-Work uses computational power c) Proof-of-Stake requires more energy than Proof-of-Work d) None of the above
b) Proof-of-Stake requires ownership of cryptocurrency to validate transactions, Proof-of-Work uses computational power
What is the primary disadvantage of using Proof-of-Stake? a) It leads to centralization b) It consumes too much energy c) It has slower transaction speeds d) It uses less secure cryptographic techniques
a) It leads to centralization
Which method in Ethereum is used for preventing infinite loops and runaway computations? a) Gas b) Ether c) Nonce d) Proof-of-Stake
a) Gas
What is a possible vulnerability in smart contracts that can be exploited by hackers? a) Gas overflows b) Reentrancy c) Invalid opcode usage d) Lack of consensus
b) Reentrancy
What is Ethereum’s consensus algorithm used to secure the blockchain? a) Proof-of-Work b) Proof-of-Stake c) Proof-of-Authority d) Proof-of-Burn
b) Proof-of-Stake
Which of the following makes Ethereum a Turing-complete platform? a) Its use of Solidity b) The Ethereum Virtual Machine (EVM) c) Its use of Gas d) The ability to create smart contracts
b) The Ethereum Virtual Machine (EVM)
What is Ethereum gas used for? a) To store Ethereum transactions b) To calculate the difficulty of Ethereum mining c) To pay for computational work on the Ethereum network d) To validate smart contracts
c) To pay for computational work on the Ethereum network
What is the function of a smart contract? a) To store financial records b) To execute contract terms automatically based on predefined conditions c) To provide a centralized control d) To create mining pools
b) To execute contract terms automatically based on predefined conditions
What is a common use case for Ethereum smart contracts? a) Online transactions b) Voting c) Supply chain management d) All of the above
d) All of the above
Which tool is commonly used to test and deploy smart contracts in Ethereum development? a) Remix b) Truffle c) Hardhat d) All of the above
d) All of the above
What is an Oracle in the context of Ethereum? a) A cryptocurrency exchange b) A mechanism to fetch real-world data for smart contracts c) A mining pool d) A decentralized database
b) A mechanism to fetch real-world data for smart contracts
Which of the following Ethereum upgrades helped reduce energy consumption by 99.95%? a) Proof-of-Work b) Proof-of-Stake c) Proof-of-Authority d) Sharding
b) Proof-of-Stake
What is the Ethereum gas tracker used for? a) To check the current gas price for transactions b) To track Ethereum network speed c) To monitor gas usage in mining d) To manage Ethereum wallets
a) To check the current gas price for transactions
What does the term ‘minting’ refer to in the context of Proof-of-Stake? a) Creating new coins through mining b) Creating new blocks and adding them to the blockchain c) Creating gas for transaction fees d) Deploying new smart contracts
b) Creating new blocks and adding them to the blockchain
What role does the proof() function serve in the smart contract demonstration? a) It generates a new block b) It stores the signature of a document c) It computes the transaction hash d) It calculates gas usage
b) It stores the signature of a document
What is the advantage of using a map instead of an array for storing data in Ethereum smart contracts? a) Faster lookup times b) Lower gas usage c) More storage space d) Both a and b
d) Both a and b
What is the name of the development environment that helps with Ethereum contract creation and deployment? a) Remix b) Hardhat c) Truffle d) All of the above
d) All of the above
Which of the following is NOT an Ethereum feature? a) Ethereum Virtual Machine (EVM) b) Gas pricing for transaction cost c) Consensus through Proof-of-Work d) Smart contract language Ruby
d) Smart contract language Ruby
