Blockchain Architecture and Its Core Components BBLC Practice Questions (Page 1)

Questions 1–5

1. 1foundation · easy

   Which of the following is a core component of a blockchain that stores a list of validated transactions?

   • ASmart contract
   • BConsensus algorithm
   • CNode
   • DBlock
   Reveal Solution Discussion Select an answer first
2. 2expert · hard

   A user sends a transaction to a public blockchain, but after 10 minutes it is still not confirmed. The transaction was broadcast and is visible in the mempool. Which is the most likely cause?

   • AThe transaction was rejected by the network because it was not signed by a miner.
   • BThe transaction fee is too low relative to the current network congestion, so miners prioritize other transactions.
   • CThe transaction was broadcast to only one node and cannot reach the rest of the network.
   • DThe transaction is waiting for a central authority to approve it before it can be included in a block.
   Reveal Solution Discussion Select an answer first
4. 3application · medium

   A startup is building a decentralized application for peer-to-peer energy trading. They want to avoid the energy consumption of Proof of Work while still allowing anyone to participate in validating transactions. Which consensus mechanism best fits this requirement?

   • AProof of Burn (PoB)
   • BProof of Stake (PoS)
   • CProof of Authority (PoA)
   • DPractical Byzantine Fault Tolerance (PBFT)
   Reveal Solution Discussion Select an answer first
5. 4expert · hard

   A company plans to deploy a smart contract that manages insurance payouts. They are concerned about the 'oracle problem' — the need to bring real-world data (e.g., weather data) onto the blockchain. Which approach best addresses this concern while maintaining the benefits of smart contracts?

   • AUse a decentralized oracle network that aggregates data from multiple independent sources and feeds it to the smart contract.
   • BUse a sidechain that is connected to the internet and then relay the data to the main chain.
   • CHave the smart contract directly access the internet to fetch weather data.
   • DStore the weather data on-chain manually by a trusted administrator before each payout.
   Reveal Solution Discussion Select an answer first
6. 5foundation · easy

   Which of the following best describes the overall architecture of a typical blockchain system?

   • AA client-server model where thin clients rely on a central authority for all data access
   • BA layered structure with a data layer, network layer, consensus layer, and application layer working together
   • CA peer-to-peer network with no defined layers, where every node performs all functions identically
   • DA single centralized server that stores all transaction records and validates every request
   Reveal Solution Discussion Select an answer first