Blockchain CBDE Exam Questions Instant Access

Question 1

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 2

Address.call.value():

Asends the gas stipend of 2300 gas and returns a false on error.

Bsends all the gas along and cascades exceptions.

Csends all the gas along and returns a false on error.

Dsends the gas stipend of 2300 gas and cascades exceptions.

Answer : C

Question 3

Checking the balance of an address inside a loop of a smart contract constantly:

Adoesn't cost any gas.

Bcost gas every time we check the balance.

Answer : B

Question 4

Function and Variable Visibility:

Aa function that is marked as internal cannot be called by other contracts, unless the function is used by a derived contract. Private Functions cannot be called by any other outside contract and public variables are generating automatically a getter function.

Ba function that is marked as external can never be called internally. Private functions can also be called by derived contracts using inheritance. Private variables are accessible also in derived contracts.

Answer : A

Question 5

Transactions containing the same data to create the same smart contract are:

Aalways having the same signature.

Bhaving a different signature because of the nonce which changes upon every transaction.

Answer : B

Question 6

On a consortium network:

Aeverybody can become a miner, everybody can send transactions and everything is public.

Busually only a few selected nodes can be miners. Transactions can be further limited.

Answer : B

Question 7

A Hashing Algorithm is deterministic. What does it mean?

Ait always produces the same output given the same input.

Bit uses equally distributed data to produce the output given a long input.

Cit shouldn't be possible to re-generate the input given the output.

Answer : A

Blockchain BTA Certified Blockchain Developer - Ethereum CBDE Exam Questions