Certified Bitcoin Professional Practice Exam

How is Bitcoin's block solving rate sustained?

1. Automatic market adjustments

2. Regular user donations

3. Difficulty adjustments

4. Increased mining rewards

The correct answer is: Difficulty adjustments

The mechanism known as difficulty adjustments is central to sustaining Bitcoin's block solving rate. This process occurs approximately every 2016 blocks, or about every two weeks. The Bitcoin network automatically adjusts the difficulty of the puzzles that miners must solve to add a new block to the blockchain based on the time it took to mine the previous 2016 blocks. If miners are solving blocks too quickly, the difficulty will increase, making it harder to find new blocks, thereby slowing the rate of block creation to the desired average of one block every ten minutes. Conversely, if blocks are being solved too slowly, the difficulty will decrease, allowing miners to solve blocks more easily and increasing the block solving rate. This self-regulating mechanism ensures that, regardless of the total amount of computational power dedicated to mining, Bitcoin maintains a steady and predictable block generation time. Other methods, such as automatic market adjustments, do not play a role in maintaining the block solving rate. User donations are not a mechanism inherent to the blockchain's operational structure, and while increased mining rewards can incentivize miners, they do not directly adjust the rate at which blocks are solved. Therefore, difficulty adjustments are critically important in maintaining the balance and consistency of block creation in the Bitcoin network.