Bitcoin Network and Its Transactions BDC Practice Questions (Page 3)

Questions 11–15

1. 11application · medium

   A merchant wants to accept Bitcoin payments and needs to decide how many confirmations to wait before treating a payment as final. The payment amount is small (e.g., a coffee). Which confirmation policy is most appropriate?

   • AWait for one confirmation, which is sufficient for small-value transactions.
   • BWait for the transaction to be included in a block and then wait for the next block to be mined.
   • CWait for six confirmations, which is the standard for high-value transactions.
   • DWait for zero confirmations and rely on the transaction being broadcast.
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2. 12application · medium

   A user broadcasts a Bitcoin transaction with a low fee. After 30 minutes, the transaction is still not confirmed. What is the most likely reason?

   • AThe transaction is invalid because it spends an output that is already spent.
   • BThe transaction is waiting in the mempool because miners are prioritizing transactions with higher fees.
   • CThe transaction was not signed correctly.
   • DThe transaction was broadcast to only one node, which is offline.
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4. 13expert · medium

   A developer is building a wallet that must handle a transaction with multiple inputs and outputs. The wallet needs to ensure that the transaction is valid and does not accidentally create a fee that is too high. What is the most reliable way to calculate the fee?

   • AMultiply the number of inputs by a fixed fee rate.
   • BUse the fee rate recommended by the wallet's fee estimator, which is always accurate.
   • CCalculate the fee as the sum of all output values minus the sum of all input values.
   • DSum the values of all inputs and subtract the sum of all output values.
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5. 14foundation · easy

   How is the transaction fee for a Bitcoin transaction determined?

   • AIt is a flat rate charged by the Bitcoin network
   • BIt is the difference between the total inputs and total outputs
   • CIt is set by the recipient and included in the output script
   • DIt is a fixed percentage of the transaction amount
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6. 15foundation · easy

   In the Bitcoin network, what is the primary role of a full node?

   • ATo provide a lightweight interface for users to send and receive Bitcoin without downloading the blockchain
   • BTo create new blocks by solving a cryptographic puzzle and broadcast them to the network
   • CTo act as a central authority that approves transactions and prevents double-spending
   • DTo validate transactions and blocks against consensus rules and maintain a copy of the blockchain
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