blockchain cbde practice test

Ethereum

Last exam update: Nov 27 ,2025
Page 1 out of 7. Viewing questions 1-15 out of 102

Question 1

Consensus is reached:

  • A. by the miner nodes which make sure that a transaction is valid.
  • B. by every single node in the blockchain network executing the same transaction.
  • C. by a cryptographic secure signature algorithm called ECDSA which makes sure that cheating is impossible.
Mark Question:
Answer:

B

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 2

Smart Contracts can be written in:

  • A. Java, C++, Solidity and JavaScript, because the Ethereum Blockchain is completely language agnostic and cross compilers exist for every major language.
  • B. Solidity, Viper, LLL and Serpent, because those are high level languages that are compiled down to bytecode.
  • C. Solidity and JavaScript, because those are the official first implementations for Distributed applications and the Blockchain supports those languages fully.
Mark Question:
Answer:

B

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 3

Solidity gets compiled:

  • A. to bytecode that can't be understood by humans.
  • B. to bytecodes which are essentially opcodes running instruction by instruction.
Mark Question:
Answer:

B

User Votes:
A
50%
B
50%
Discussions
vote your answer:
A
B
0 / 1000

Question 4

Having a bug-bounty program early on:

  • A. can help to engage the community in testing your smart contracts and therefore help to find bugs early.
  • B. might be a burden as it is an administrative overhead mainly.
  • C. is completely useless. Who wants to test beta-ware software? It’s better to start with the bug- bounty program after the contract is released on the main-net.
Mark Question:
Answer:

A

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 5

Which is the right order for Denominations?

  • A. Wei, Finney, Szabo, Ether, Tether.
  • B. Finney, Szabo, Mether, Gwei.
  • C. Gwei, Szabo, Finney, Ether.
Mark Question:
Answer:

C

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 6

The nonce-field in a transaction is used:

  • A. to protect against replay attacks.
  • B. to have an additional checksum for transactions.
  • C. to sum up all ethers sent from that address.
Mark Question:
Answer:

A

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 7

Which statement is true about the EVM?

  • A. While the EVM is Sandboxed, it isn't as powerful as the Bitcoin Network, because it's not Turing Complete.
  • B. The EVM can't access hardware layers or anything outside a blockchain node because it's sandboxed.
  • C. The EVM is extremely powerful, turing complete and perfect for doing computational intensive things, because of the direct access to the graphics card.
Mark Question:
Answer:

C

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 8

DApps are:

  • A. great, because they cut the middle man, run on a trusted platform, apply logic to the blockchain where already economic assets are running and thus allow peer to peer trade.
  • B. an amazing way to create new applications. Those applications run entirely separated from other applications on the platform and allow for logical interactions. They can't access any funds to add an additional layer of trust.
  • C. a new way of applying logical operations for banks and big financial institutions. This way they can reduce the staff while operating at increased security.
Mark Question:
Answer:

B

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 9

To get most out of the blockchain, it is best:

  • A. to use it for the whole business logic. It’s always best to have everything in once place.
  • B. to use it only for things which need the benefits of the blockchain.
Mark Question:
Answer:

B

User Votes:
A
50%
B
50%
Discussions
vote your answer:
A
B
0 / 1000

Question 10

A Hashing Algorithm is deterministic. What does it mean?

  • A. it always produces the same output given the same input.
  • B. it uses equally distributed data to produce the output given a long input.
  • C. it shouldn't be possible to re-generate the input given the output.
Mark Question:
Answer:

A

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 11

What's the correct scientific notation?

  • A. 1 Ether = 10^18 wei, 10^9 Gwei, 10^3 Finney
  • B. 1 Ether = 10^19 wei, 10^13 Gwei, 10^3 Finney
  • C. 1 Ether = 10^16 wei, 10^13 Gwei, 10^3 Finney
  • D. 1 Ether = 10^18 wei, 10^6 Gwei, 10^6 Finney
Mark Question:
Answer:

A

User Votes:
A
50%
B
50%
C
50%
D
50%
Discussions
vote your answer:
A
B
C
D
0 / 1000

Question 12

What are Private Keys used for?

  • A. To Protect the Public Keys by being cryptographically significant.
  • B. To Sign Transactions And To Derive an Address From.
  • C. To Generate An Address which can sign transactions.
Mark Question:
Answer:

B

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 13

Public Keys vs. Private Keys. Which statement is true?

  • A. The Public Key is for Signing Transactions, the Private Key must be given out to verify the signature.
  • B. The Private Key signs transactions, the Public Key can verify the signature.
  • C. The Private Key is to generate a Public Key. The Public Key can sign transactions, the address is here to verify the transactions.
Mark Question:
Answer:

B

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 14

Proof of Work (PoW) vs. Proof of Stake.

  • A. PoW is computationally intensive which requires lots of energy. On the other hand, miners earn straightforward a reward for mining a block and incorporating transactions.
  • B. PoW is better than PoS, because with PoS we increase the amount of energy spent on the network.
  • C. PoS is mining with specialized new hardware that has to be purchased with a stack of Ether in the network. Hence the Name: Proof of Stake, which derives from Stack.
Mark Question:
Answer:

A

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000

Question 15

Externally Owned Accounts:

  • A. can be destroyed using the selfdestruct keyword. This way all remaining ether will be sent to the receiver address, regardless if they have a fallback function or not.
  • B. are bound to a private key which is necessary to sign transactions outgoing from that account.
  • C. are logical opcodes running on the ethereum blockchain very similar to smart contracts.
Mark Question:
Answer:

B

User Votes:
A
50%
B
50%
C
50%
Discussions
vote your answer:
A
B
C
0 / 1000
To page 2