Ethereum Architecture and Transaction Lifecycle BBLC Practice Questions (Page 8)

Questions 36–40

1. 36foundation · easy

   How does a transaction trigger the execution of a smart contract on Ethereum?

   • AThe transaction's 'to' field specifies the contract address, and the 'data' field contains the function call and arguments
   • BThe transaction's 'gasLimit' field contains the function signature
   • CThe transaction's 'value' field contains the function name
   • DThe transaction's 'nonce' field determines which function to execute
   Reveal Solution Discussion Select an answer first
2. 37expert · hard

   A smart contract function modifies a state variable and emits an event. After the transaction is mined, a developer checks the receipt and sees the event in the logs. What does this confirm?

   • AThe state change was executed and the event was emitted, but the event does not prove the state change is permanent.
   • BThe event is stored on-chain and can be used to reconstruct the entire state.
   • CThe event proves that the transaction was successful and the state change is final.
   • DThe state change is permanent and cannot be reverted.
   Reveal Solution Discussion Select an answer first
4. 38application · medium

   A developer is writing a smart contract that needs to transfer Ether to a user. The contract calls a function that sends Ether. Which statement is true?

   • AThe contract creates a new transaction to send Ether to the user.
   • BThe contract sends a message to the user's EOA, which is executed within the same transaction.
   • CThe user must sign a transaction to receive the Ether.
   • DThe contract's transfer is a message that requires a separate gas payment.
   Reveal Solution Discussion Select an answer first
5. 39application · medium

   A blockchain consultant is explaining Ethereum's transition to Proof of Stake. A client asks how a new block is finalized under PoS. Which statement is accurate?

   • AValidators are selected to propose a block, and other validators attest to it; after enough attestations, the block is finalized.
   • BMiners compete to solve a cryptographic puzzle, and the first to solve it proposes the block.
   • CA central authority selects a validator to propose a block, and other validators must accept it.
   • DAll validators simultaneously propose blocks, and the network merges them into one.
   Reveal Solution Discussion Select an answer first
6. 40expert · hard

   A smart contract needs to send ETH to another contract. The sending contract calls `address.call{value: 1 ether}("")`. What is a key difference between this message call and a transaction from an EOA?

   • AThe message call is broadcast to the network as a separate transaction.
   • BThe message call requires a separate nonce and gas limit.
   • CThe message call can only be executed if the receiving contract has a payable fallback function.
   • DThe message call does not have its own signature and is executed within the original transaction's context.
   Reveal Solution Discussion Select an answer first