Smart Contracts and dApps Flashcards
7 cards from real Blockchain Technology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Smart Contracts and dApps flashcards as text
What is a 'proxy contract' pattern used for in Ethereum smart contract development?
Answer: Enabling upgradeable smart contracts
Proxy contracts delegate calls to an implementation contract, allowing the logic to be upgraded by pointing to a new implementation while preserving storage and address.
In the context of dApps, what is a 'wallet connect' flow primarily used for?
Answer: Allowing users to sign transactions without exposing keys to the dApp
WalletConnect establishes a secure channel between a dApp and a mobile or hardware wallet so users can approve transactions without sharing private keys.
What does 'gas limit' represent in an Ethereum transaction?
Answer: The maximum amount of computational work the sender authorizes
The gas limit is the maximum units of computation the sender permits for the transaction; unused gas is refunded and exhausted gas causes a revert.
Which consensus mechanism does Ethereum use after 'The Merge' in 2022?
Answer: Proof of Stake
After The Merge, Ethereum switched from Proof of Work to Proof of Stake, where validators stake 32 ETH to propose and attest blocks.
What is the role of an 'event' in a Solidity smart contract?
Answer: To log data cheaply that off-chain clients can subscribe to
Events write data to transaction logs, which are cheaper than storage and can be monitored by off-chain applications via Web3 subscriptions.
In DeFi, what is an 'AMM' (Automated Market Maker)?
Answer: A protocol that prices assets using liquidity pool formulas instead of order books
AMMs like Uniswap use mathematical formulas (e.g., x*y=k) with liquidity pools to determine asset prices and enable permissionless token swaps.
What distinguishes an ERC-721 token from an ERC-20 token?
Answer: ERC-721 tokens are non-fungible (unique); ERC-20 tokens are fungible (interchangeable)
ERC-721 tokens each have a unique token ID representing a distinct asset (NFT), whereas ERC-20 tokens are interchangeable like currency.