• #A
    #B
    #C
    #D
    Explanation:
    Mainnets often have stricter gas limits and higher costs than testnets. A function that runs fine on testnet may exceed block gas limits in production. Developers should simulate deployments and optimize loops before mainnet release
  • Difficulty - Medium
    Total Plays - 6
    Allowed Time - 10 sec
    Best time - 2.132 sec

    When does a fallback trigger?

    Tip: Click "Play" to reveal options and start playing.
    #A
    #B
    #C
    #D
    Explanation:
    The fallback() function runs when a transaction calls a non-existent function or sends data without matching any signature. It’s essential for proxy contracts but must be written carefully to avoid gas griefing and reentrancy risks.
  • Difficulty - Medium
    Total Plays - 3
    Allowed Time - 10 sec
    Best time - 1.483 sec

    What does delegatecall do?

    Tip: Click "Play" to reveal options and start playing.
    #A
    #B
    #C
    #D
    Explanation:
    delegatecall lets one contract run another’s code while keeping its own storage and balance. It’s powerful but risky — if the target contract has malicious logic, it can overwrite your state variables or drain funds. Auditors always flag unsafe delegatecalls
  • Difficulty - Medium
    Total Plays - 15
    Allowed Time - 10 sec
    Best time - 1.968 sec

    What is a rollup?

    Tip: Click "Play" to reveal options and start playing.
    #A
    #B
    #C
    #D
    Explanation:
    Rollups are Layer 2 blockchain scaling solutions that bundle multiple transactions off-chain and then post cryptographic proofs to the main chain. This reduces gas fees and increases transaction speed while maintaining the security and decentralization of the base blockchain. Rollups are key to Ethereum scalability and the future of high-performance Web3 applications.
  • #A
    #B
    #C
    #D
    Explanation:
    MEV (Maximum Extractable Value) refers to profits gained by reordering or inserting transactions in a block. It’s a major focus in blockchain security and DeFi optimization, influencing how validators and searchers interact with the mempool.
  • Difficulty - Medium
    Total Plays - 18
    Allowed Time - 10 sec
    Best time - 0.936 sec

    What is sharding in blockchains?

    Tip: Click "Play" to reveal options and start playing.
    #A
    #B
    #C
    #D
    Explanation:
    Sharding is a blockchain scalability technique that divides the entire network’s data into smaller, manageable pieces called shards. Each shard processes its own transactions and smart contracts, improving network speed, performance, and efficiency. This concept is key for scalable blockchain infrastructure like Ethereum 2.0 and future Web3 ecosystems.
  • #A
    #B
    #C
    #D
    Explanation:
    A Blockchain QA Analyst is responsible for testing smart contracts, dApps, and blockchain networks to ensure they work as intended. They identify bugs, check performance, and validate security, which is critical for building trust in decentralized applications. This role is increasingly important in blockchain careers, as companies rely on QA analysts to deliver reliable and secure Web3 products.
  • #A
    #B
    #C
    #D
    Explanation:
    Bitcoin uses the SHA-256 cryptographic hash function to secure transactions and link blocks in the blockchain. This algorithm produces a fixed 256-bit output, ensuring immutability and resistance to tampering. By using SHA-256, Bitcoin maintains trust, decentralization, and data integrity across the network
  • Difficulty - Medium
    Total Plays - 31
    Allowed Time - 10 sec
    Best time - 0.959 sec

    What does zk-SNARK stand for?

    Tip: Click "Play" to reveal options and start playing.
    #A
    #B
    #C
    #D
    Explanation:
    zk-SNARKs are zero-knowledge proofs that improve blockchain privacy and scaling by verifying transactions without revealing sensitive data.
  • #A
    #B
    #C
    #D
    Explanation:
    BFT-based (Byzantine Fault Tolerant) consensus mechanisms achieve instant or near-instant finality by requiring agreement among validators in just one round of communication, allowing transactions to be finalized in seconds—faster than PoW, PoS, or DPoS.
  • #A
    #B
    #C
    #D
    Explanation:
    BFT-based (Byzantine Fault Tolerant) consensus mechanisms achieve instant or near-instant finality by requiring agreement among validators in just one round of communication, allowing transactions to be finalized in seconds—faster than PoW, PoS, or DPoS.
  • Difficulty - Medium
    Total Plays - 53
    Allowed Time - 10 sec
    Best time - 2.094 sec

    What is the EVM?

    Tip: Click "Play" to reveal options and start playing.
    #A
    #B
    #C
    #D
    Explanation:
    The Ethereum Virtual Machine (EVM) is a global, decentralized computer that executes smart contracts on the Ethereum blockchain. It ensures every node produces the same results, keeping the network consistent and secure.
  • Difficulty - Medium
    Total Plays - 44
    Allowed Time - 10 sec
    Best time - 1.790 sec

    What is front-running in DeFi?

    Tip: Click "Play" to reveal options and start playing.
    #A
    #B
    #C
    #D
    Explanation:
    Traders exploit transaction ordering for profit.
  • #A
    #B
    #C
    #D
    Explanation:
    A 51% attack happens when one miner/validator controls over half the network’s power or stake. This lets them rewrite history or double-spend coins, threatening security. It’s rare on large chains like Bitcoin but a risk for smaller ones.
  • Difficulty - Medium
    Total Plays - 64
    Allowed Time - 10 sec
    Best time - 0.929 sec

    What does OpenZeppelin provide?

    Tip: Click "Play" to reveal options and start playing.
    #A
    #B
    #C
    #D
    Explanation:
    OpenZeppelin offers audited, reusable smart contract templates, like ERC-20 and ERC-721 implementations. It enhances security and saves development time.
Home Channels Search Login Register