Ethereum's Purpose, Ecosystem, and Evolution BDC Practice Questions (Page 4)

Questions 16–20

1. 16application · medium

   A developer wants to deploy a smart contract to the Ethereum mainnet. Which set of tools is necessary for this task?

   • AA node and a wallet
   • BA compiler (e.g., Solc), a deployment tool (e.g., Truffle), and a funded wallet
   • CA testnet and a faucet
   • DA block explorer and a mining rig
   Reveal Solution Discussion Select an answer first
2. 17expert · hard

   A developer is troubleshooting a DApp that intermittently fails to read the latest state from a smart contract. The DApp uses a node provider, and the developer suspects that the provider's node is behind the latest block. Which action would most directly address this issue?

   • ADeploy the contract to a testnet
   • BUse a WebSocket connection to subscribe to new block headers and update the DApp's state accordingly
   • CIncrease the gas limit on the DApp's transactions
   • DSwitch to a different wallet provider
   Reveal Solution Discussion Select an answer first
4. 18application · medium

   A developer is building a DApp that needs to allow users to sign transactions and interact with smart contracts from a web browser. Which Ethereum ecosystem component should be integrated?

   • AA block explorer
   • BA browser wallet like MetaMask
   • CA smart contract compiler
   • DA mining pool
   Reveal Solution Discussion Select an answer first
5. 19expert · hard

   A developer is building a DApp that requires users to prove ownership of a private key without revealing it. Which Ethereum ecosystem component or feature can be used to achieve this?

   • AA wallet like MetaMask, which stores the private key locally.
   • BA block explorer, which shows transaction history.
   • CDigital signatures, which allow users to sign messages with their private key and verify with their public key.
   • DA smart contract that stores the private key.
   Reveal Solution Discussion Select an answer first
6. 20application · medium

   A startup wants to deploy a decentralized application where users vote on proposals, and the results must be tamper-proof and auditable by anyone. They plan to store the voting logic and vote tallies on-chain. Which Ethereum ecosystem component should they primarily use to interact with the deployed contract from a web browser?

   • AAn Ethereum name service (ENS) domain
   • BA full node running Geth
   • CA hardware wallet
   • DA JavaScript library such as ethers.js
   Reveal Solution Discussion Select an answer first