CBE Foundational Concepts 5

Question 1

What is the maximum total supply of bitcoin?

Accepted Answer

21 million

Answer

Bitcoin's protocol caps the total supply at 21 million coins.

Question 2

How often does Bitcoin's block subsidy halve?

Accepted Answer

Every 210,000 blocks

Answer

The block reward halves every 210,000 blocks, about every four years.

Question 3

In September 2022, Ethereum moved from Proof-of-Work to Proof-of-Stake. What is this event called?

Accepted Answer

The Merge

Answer

The Merge joined Ethereum's execution layer with the Beacon Chain and switched it to Proof-of-Stake.

Question 4

What does a 51% attack let an attacker do?

Accepted Answer

Reorganize recent blocks and double-spend their own coins

Answer

Majority hash power lets an attacker rewrite recent history to double-spend, but not forge signatures or break supply rules.

Question 5

Which hash function does Ethereum mainly use?

Accepted Answer

Keccak-256

Answer

Ethereum uses Keccak-256, a variant of the SHA-3 family, for addresses and hashing.

CBE - Certified Blockchain Expert Practice Test