Free Blockchain CBDE Exam Questions

Become Blockchain Certified with updated CBDE exam questions and correct answers

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Total 102 Questions | Updated On: Jun 06, 2025

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Question 1

When using assert to check invariants and it evaluates to false:

A : l gas is consumed.

B : l remaining gas is returned

Answer: A

Question 2

The Fallback function:

A : nnot receive Ether, not even by adding the payable modifier

B : n contain as much logic as you want, but it’s better to keep it short and not exceed the gas stipend of 2300 gas

C : n be used to avoid receiving ether

Answer: B

Question 3

To communicate with an Ethereum node via [removed]

A : library you use must make use of the JSON-RPC Interface of an Ethereum Node

B : t Implement the Ethereum Protocol to connect to other Ethereum Nodes.

C : t use Web3.js, which is closed source to communicate to other Ethereum Nodes.

Answer: A

Question 4

Smart Contracts can be written in:

A : va, C++, Solidity and JavaScript, because the Ethereum Blockchain is completely language agnostic and cross compilers exist for every major language

B : lidity, Viper, LLL and Serpent, because those are high level languages that are compiled down to bytecode.

C : lidity and JavaScript, because those are the official first implementations for Distributed applications and the Blockchain supports those languages fully.

Answer: B

Question 5

When considering smart contracts and the blockchain it's good

A : move all existing logic to the blockchain, so everything runs on the same system. This way it might be more complex, but easier to maintain

B : move only those parts to the blockchain that really need the blockchain. This way smart contracts can be easier to read, easier to test and are not so complex

C : move those parts to the blockchain that deal with Ether transfers. All other parts can remain in traditional database systems. This way only the value-transfer is on the blockchain.

Answer: B

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Total 102 Questions | Updated On: Jun 06, 2025

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