Labour Day Special - Limited Time 65% Discount Offer - Ends in 0d 00h 00m 00s - Coupon code: top65certs

Blockchain CBDE Dumps

Page: 1 / 4
Total 102 questions

BTA Certified Blockchain Developer - Ethereum Questions and Answers

Question 1

Truffle has an integrated in-memory blockchain which makes unit-testing very easy:

Options:

A.

True, but it's still good to use Ganache, or even a real private network for testing.

B.

False, it's necessary to use Ganache or even a real private network for testing.

Question 2

For Rapid Development Cycles it's good:

Options:

A.

to deploy to the main-network as quickly as possible.

B.

to use in-memory blockchain simulations, because mining works instantaneously.

C.

to use a private network at all times, because this is the closest you get to the real network.

Question 3

You interact with a smart contract and see a gas usage of 50,000 gas with a gas cost of 15Gwei.

How much Ether would you have to pay to the miner?

Options:

A.

750,000,000,000,000 Wei

B.

750,000,000,000 Wei

C.

750,000,000 Wei

D.

A flat fee of 1 Ether

Question 4

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

Options:

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

What are Ethereum Nodes?

Options:

A.

Programs implementing the Ethereum Protocol to talk to each other and JSON-RPC interfaces to talk to the outside world.

B.

A Java-Script library to compile and run Solidity Code.

C.

A Framework for deploying and running smart contract in a decentralized way.

Question 6

Files can be imported:

Options:

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 7

Address.send():

Options:

A.

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

B.

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

Question 8

Solidity files:

Options:

A.

can't be split across multiple files, everything should be in one single file.

B.

can be split across multiple files, but every contract must be in a file with the same name as the contract itself.

C.

can be spread across multiple files. To import all contract from a file you can use "import 'myfile.sol'. To import Contract MyContract from myfile.sol you use "import {MyContract as SomeContract} from 'myfile.sol';".

Question 9

Assert is used:

Options:

A.

to check internal states that should never happen.

B.

to check input arguments from users.

Question 10

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

Options:

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.

Question 11

The difference between address.send() and address.transfer() is:

Options:

A.

.send returns a Boolean and .transfer throws an exception on error. Both just forward the gasstipend of 2300 gas and are considered safe against re-entrancy.

B.

.send throws an exception and .transfer returns a Boolean on error. Both just forward the gasstipend of 2300 gas and considered safe against re-entrancy

C.

.send returns a Boolean and .transfer throws an exception on error. .send is considered dangerous, because it sends all gas along, while .transfer only sends the gas stipend of 2300 gas along

D.

.send and .transfer are both considered low-level functions which are dangerous, because they send all gas along. It's better to use address.call.value()() to control the gas-amount.

Question 12

Which statement is true about the EVM?

Options:

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.

Question 13

It’s possible to access the blockchain via an Ethereum Node:

Options:

A.

only via JavaScript because there is the proprietary Web3.js library.

B.

by any programming language, as long as it adheres to the JSON-RPC standard.

Question 14

PoS:

Options:

A.

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

B.

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

Question 15

DApps are:

Options:

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.

Page: 1 / 4
Total 102 questions