Question 1

Consensus is reached:

Accepted Answer

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. 
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. B

Question 2

What are Private Keys used for?

Accepted Answer

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. 
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. B

Question 3

To develop smart contracts:

Accepted Answer

A)  it's good to start with a local in-memory blockchain with unit tests but then deploy to the mainnet as rapidly as possible. 
B)  it's good to start with a local in-memory blockchain with unit-tests. Then, in the next step, debug and test the smart contract on a test-net like Ropsten or Rinkeby with beta customers to iron out last issues before deploying it to the main-net. 
C)  it's good to start with a test-net with beta-customers like on the Rinkeby or Ropsten testnet, before testing it locally on an in-memory blockchain simulation such as Ganache. Then deploy it to the main-net. 
A)  it's good to start with a local in-memory blockchain with unit tests but then deploy to the mainnet as rapidly as possible. 
B)  it's good to start with a local in-memory blockchain with unit-tests. Then, in the next step, debug and test the smart contract on a test-net like Ropsten or Rinkeby with beta customers to iron out last issues before deploying it to the main-net. 
C)  it's good to start with a test-net with beta-customers like on the Rinkeby or Ropsten testnet, before testing it locally on an in-memory blockchain simulation such as Ganache. Then deploy it to the main-net. B

Question 4

When you are programming a game like poker of battleships where you need to hide opponents values is:

Accepted Answer

A)  with private state variables. This way nobody else other than the smart contract itself can see the information 
B)  with external contracts holding those values. This way we can make sure that the information flow is following a clear logic and nobody else can access this information. 
C)  You can't hide anything on the blockchain, because the information is public, just the call is private which means only other smart contracts would be limited in accessing that information. 
A)  with private state variables. This way nobody else other than the smart contract itself can see the information 
B)  with external contracts holding those values. This way we can make sure that the information flow is following a clear logic and nobody else can access this information. 
C)  You can't hide anything on the blockchain, because the information is public, just the call is private which means only other smart contracts would be limited in accessing that information.

Question 5

Files can be imported:

Accepted Answer

A)  using relative and absolute paths, where the "." And the ".." depict that it's a relative path. 
B)  only via GitHub using the Repository and Username. 
C)  using the special requirefile(...) statement, which looks in a specific library path to import files. 
A)  using relative and absolute paths, where the "." And the ".." depict that it's a relative path. 
B)  only via GitHub using the Repository and Username. 
C)  using the special requirefile(...) statement, which looks in a specific library path to import files.

Question 6

To communicate with an Ethereum node via JavaScript:

Accepted Answer

A)  the library you use must make use of the JSON-RPC Interface of an Ethereum Node. 
B)  must Implement the Ethereum Protocol to connect to other Ethereum Nodes. 
C)  must use Web3.js, which is closed source to communicate to other Ethereum Nodes. 
A)  the library you use must make use of the JSON-RPC Interface of an Ethereum Node. 
B)  must Implement the Ethereum Protocol to connect to other Ethereum Nodes. 
C)  must use Web3.js, which is closed source to communicate to other Ethereum Nodes.

Question 7

When solidity is compiled then also Metadata is generated:

Accepted Answer

A)  the Metadata contains the ABI Array, which defines the Interface to interact with the Smart Contract. Metadata can also contain the address of the smart contract when it gets deployed. 
B)  metadata contains the address, and the size of the smart contract. The ABI Array is generated externally upon deploying the smart contract. 
C)  the ABI array and the Metadata are not generated when solidity is compiled to bytecode, its generated by a migration software which deploys the smart contract on the blockchain. 
A)  the Metadata contains the ABI Array, which defines the Interface to interact with the Smart Contract. Metadata can also contain the address of the smart contract when it gets deployed. 
B)  metadata contains the address, and the size of the smart contract. The ABI Array is generated externally upon deploying the smart contract. 
C)  the ABI array and the Metadata are not generated when solidity is compiled to bytecode, its generated by a migration software which deploys the smart contract on the blockchain.

Question 8

Multi-Line Comments in Solidity are:

Accepted Answer

A)  working with either // or /// 
B)  working with /* comment */ or /** @.. natspec style */ 
C)  not possible, all comments must be single-line. 
A)  working with either // or /// 
B)  working with /* comment */ or /** @.. natspec style */ 
C)  not possible, all comments must be single-line.

Question 9

Gas costs accrue on sending a transaction:

Accepted Answer

A)  no matter the content. 
B)  only with a new smart contract deployment. 
C)  only interacting with an already deployed smart contract. 
A)  no matter the content. 
B)  only with a new smart contract deployment. 
C)  only interacting with an already deployed smart contract.

Question 10

What's the correct scientific notation?

Accepted Answer

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 
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

Question 11

Block Difficulty:

Accepted Answer

A)  is determined by the Ethereum Committee every fortnight to reflect the average amount of transaction and it cannot be influenced by the network itself. 
B)  increases when the time between mined blocks is below 10 seconds, while it decreases when the time is above 20 seconds. 
C)  increases when the time between mined blocks is below 20 seconds, while it decreases when the time is above 60 seconds. 
A)  is determined by the Ethereum Committee every fortnight to reflect the average amount of transaction and it cannot be influenced by the network itself. 
B)  increases when the time between mined blocks is below 10 seconds, while it decreases when the time is above 20 seconds. 
C)  increases when the time between mined blocks is below 20 seconds, while it decreases when the time is above 60 seconds.

Question 12

EVM assembly:

Accepted Answer

A)  is much better than Solidity and a viable alternative. 
B)  can be split across multiple files, but every contract must be in a file with the same name as the contract itself. 
C)  is another language similar to LLL, more secure than Solidity. 
A)  is much better than Solidity and a viable alternative. 
B)  can be split across multiple files, but every contract must be in a file with the same name as the contract itself. 
C)  is another language similar to LLL, more secure than Solidity.

Question 13

What is the difference between ERC20 and ERC721 Tokens in simple terms?

Accepted Answer

A)  The tokens of a certain ERC20 symbol are all the same, the tokens of an ERC721 symbol are all different. So, ERC20 tokens are fungible, while ERC721 tokens are non-fungible. 
B)  The tokens of a certain ERC20 symbol are all different, the tokens of an ERC721 symbol are all the same. So, ERC20 tokens are non-fungible while ERC721 tokens are fungible. 
A)  The tokens of a certain ERC20 symbol are all the same, the tokens of an ERC721 symbol are all different. So, ERC20 tokens are fungible, while ERC721 tokens are non-fungible. 
B)  The tokens of a certain ERC20 symbol are all different, the tokens of an ERC721 symbol are all the same. So, ERC20 tokens are non-fungible while ERC721 tokens are fungible.

Question 14

.Require is used:

Accepted Answer

A)  to check internal states that should never happen. 
B)  to check input arguments from users. 
A)  to check internal states that should never happen. 
B)  to check input arguments from users.

Question 15

To generate a random number:

Accepted Answer

A)  it's good to use the block timestamp, as this is always different. 
B)  it's good to use the block hash as this is clearly always very different. 
C)  it's good to use the RANDAO smart contract. 
D)  it's not possible to have a random number in a deterministic environment such as the Ethereum blockchain. 
A)  it's good to use the block timestamp, as this is always different. 
B)  it's good to use the block hash as this is clearly always very different. 
C)  it's good to use the RANDAO smart contract. 
D)  it's not possible to have a random number in a deterministic environment such as the Ethereum blockchain.

Question 16

On a consortium network:

Accepted Answer

A)  everybody can become a miner, everybody can send transactions and everything is public. 
B)  usually only a few selected nodes can be miners. Transactions can be further limited. 
A)  everybody can become a miner, everybody can send transactions and everything is public. 
B)  usually only a few selected nodes can be miners. Transactions can be further limited.

Question 17

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

Accepted Answer

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. 
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.

Question 18

The following are value types in Solidity.

Accepted Answer

A)  Integer, Boolean, Struct, Mapping and Enum. 
B)  Integer, Boolean, Enum and Addresses. 
C)  Integer, Boolean, Structs and Fixed Point Numbers. 
A)  Integer, Boolean, Struct, Mapping and Enum. 
B)  Integer, Boolean, Enum and Addresses. 
C)  Integer, Boolean, Structs and Fixed Point Numbers.

Question 19

A Hashing Algorithm is deterministic. What does it mean?

Accepted Answer

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. 
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.

Question 20

Why is Unit-Testing so important?

Accepted Answer

A)  It helps you to find bugs, regression bugs and sometimes also helps you to understand your code from different angles. 
B)  It is a great way to spend time on something that you get paid for. But ultimately it will just slow down the development process. 
A)  It helps you to find bugs, regression bugs and sometimes also helps you to understand your code from different angles. 
B)  It is a great way to spend time on something that you get paid for. But ultimately it will just slow down the development process.

Consensus is reached:

What are Private Keys used for?

To develop smart contracts:

When you are programming a game like poker of battleships where you need to hide opponents values is:

Files can be imported:

To communicate with an Ethereum node via JavaScript:

When solidity is compiled then also Metadata is generated:

Multi-Line Comments in Solidity are:

Gas costs accrue on sending a transaction:

What's the correct scientific notation?

Block Difficulty:

EVM assembly:

What is the difference between ERC20 and ERC721 Tokens in simple terms?

.Require is used:

To generate a random number:

On a consortium network:

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

The following are value types in Solidity.

A Hashing Algorithm is deterministic. What does it mean?

Why is Unit-Testing so important?

Certified Blockchain Business Foundations

BTA Certified Blockchain Developer - Hyperledger

BTA Certified Blockchain Solution Architect

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Exam 2: BTA Certified Blockchain Developer - Ethereum

Consensus is reached:

What are Private Keys used for?

To develop smart contracts:

When you are programming a game like poker of battleships where you need to hide opponents values is:

Files can be imported:

To communicate with an Ethereum node via JavaScript:

When solidity is compiled then also Metadata is generated:

Multi-Line Comments in Solidity are:

Gas costs accrue on sending a transaction:

What's the correct scientific notation?

Block Difficulty:

EVM assembly:

What is the difference between ERC20 and ERC721 Tokens in simple terms?

.Require is used:

To generate a random number:

On a consortium network:

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

The following are value types in Solidity.

A Hashing Algorithm is deterministic. What does it mean?

Why is Unit-Testing so important?

Certified Blockchain Business Foundations

BTA Certified Blockchain Developer - Hyperledger

BTA Certified Blockchain Solution Architect

Filters