Proof of Work (PoW) and Its Variations BDC Practice Questions (Page 5)

Questions 21–25

1. 21expert · hard

   A developer is implementing a PoW algorithm for a private testnet. The team wants to ensure that the difficulty adjustment is responsive to rapid changes in hash rate. They notice that the current adjustment period is too long, causing block times to fluctuate wildly. What is the best way to improve responsiveness?

   • ASwitch to a Proof of Stake mechanism to avoid difficulty adjustment entirely.
   • BUse a fixed difficulty that is set to the average hash rate.
   • CIncrease the block reward to attract more miners, stabilizing the hash rate.
   • DShorten the difficulty adjustment period so that the target is recalculated more frequently.
   Reveal Solution Discussion Select an answer first
2. 22expert · hard

   A company is comparing the environmental impact of two blockchain networks: Network A uses PoW with a memory-hard algorithm, and Network B uses PoS. The company wants to choose the more environmentally sustainable option. What is the most accurate comparison?

   • ANetwork A is more sustainable because memory-hard algorithms are more efficient than SHA-256.
   • BNetwork B is likely to consume significantly less energy because PoS does not require intensive computation.
   • CBoth networks have similar energy consumption because they both require validators to run nodes.
   • DNetwork A is more sustainable because it is more decentralized.
   Reveal Solution Discussion Select an answer first
4. 23expert · hard · select all that apply

   A blockchain developer is evaluating ways to reduce the environmental impact of a PoW-based cryptocurrency. Which of the following approaches are viable? (Select all that apply.)

   • AIncrease the block reward to incentivize miners to use renewable energy sources.
   • BImplement a hybrid consensus mechanism that combines PoW with PoS.
   • CUse a Proof of Authority mechanism, where a small set of trusted validators produce blocks.
   • DUse a PoW algorithm that is ASIC-resistant, such as RandomX, to encourage CPU mining.
   • ESwitch to a Proof of Stake consensus mechanism.
   Check answers Discussion Select an answer first
5. 24foundation · easy

   How does the Bitcoin network adjust the mining difficulty?

   • AIt changes the target hash value based on the average time taken to mine the previous 2016 blocks.
   • BIt changes the hash algorithm from SHA-256 to a different algorithm.
   • CIt changes the block size limit to affect the time needed to propagate blocks.
   • DIt changes the block reward to incentivize more or fewer miners.
   Reveal Solution Discussion Select an answer first
6. 25application · medium

   A consortium of banks wants a permissioned blockchain with fast, predictable block times and low energy consumption. They do not require open participation. Which consensus mechanism is most appropriate for their needs?

   • AProof of Stake (PoS)
   • BProof of Authority (PoA)
   • CProof of Work (PoW)
   • DDelegated Proof of Stake (DPoS)
   Reveal Solution Discussion Select an answer first