Blockchain CBDE Exam Questions Instant Access

Question 1

Block Timestamp:

Athe timestamp is based on the time zone of the miner, that is why it changes the difficulty continuously to reflect network latency.

Bthe timestamp can't be influenced by a miner and is generally considered safe to be used for randomness on the blockchain.

Cthe timestamp can be influenced by a miner to a certain degree but it's always independent from the time-zone.

Answer : C

Question 2

PoS:

Awould be better, because it can reduce the amount of energy needed for mining.

Bwould be worse, because it would increase the amount of energy needed for mining.

Answer : A

Question 3

Smart Contracts:

Aare always living on the same address, because the blockchain is deterministic. So, one account can always have one smart contract.

Bare having the same address as the EOA.

Care sitting on their own address. The Address is created from the nonce and the EOA address and could be known in advance before deploying the smart contract.

Dthe address of the smart contract is a random address which gets generated by the miner who mines the contract-creation transaction.

Answer : C

Question 4

Address.send():

Awill cascade exceptions and address.transfer() will return a false on error.

Bwill return false on error while address.transfer() will cascade transactions.

Answer : B

Question 5

Go-Ethereum vs. Ganache:

Aboth are the same, just implemented in a different language.

Bwith Go-Ethereum you get a real blockchain node where you can create your own local private network, connect to Test-Networks or the Main-Net, while with Ganache you get an in-memory blockchain simulation.

Cwith Ganache you get a real blockchain node where you can connect to the Test-Networks Rinkeby and Ropsten.

Answer : B

Question 6

View and Pure Functions:

Aa function marked as pure can change the state, while a view function can only return static calls.

Ba function marked as view can never access state variables, while pure functions are here to return only one value.

Ca view function can access state variables, but not write to them. A Pure function cannot modify or read from state.

Answer : C

Question 7

The Fallback function:

Acannot receive Ether, not even by adding the payable modifier.

Bcan contain as much logic as you want, but it's better to keep it short and not exceed the gas stipend of 2300 gas.

Ccan be used to avoid receiving ether.

Answer : B

Blockchain BTA Certified Blockchain Developer - Ethereum CBDE Exam Questions