Ethereum Developer Test 3

Question 1

Which eth2 client launched the first testnet that allowed community participation before anyone else?

Accepted Answer

Nimbus

Answer

Teku

Answer

Prysym Lighthouse

Question 2

When using the assert command to verify invariants and it returns false

Accepted Answer

All gas is used up.

Answer

The entire gas supply is returned.

Answer

All of the statement are false.

Question 3

If you require more precise functionality than what solidity provides by default

Accepted Answer

Inline-assembly can be used to improve controls.

Answer

Viper, an experimental assembly-like language designed to provide additional flexibility, is an option.

Answer

You need to import assembly files that have already been hard-copied into the compiled solidity file's bytecode.

Question 4

Use of assert is to...

Accepted Answer

Examine user input arguments

Answer

Check internal conditions that ought to never occur

Answer

All of the above

Question 5

Which EIP number applies to the Hybrid Casper FFG proposal?

Accepted Answer

1011

Answer

1110

Answer

1010

Answer

1000

Question 6

This would be the appropriate syntax if contract MyContractA is derived from contract MyContractB:

Accepted Answer

contract MyContractA is MyContractB { ... }

Answer

contract MyContractB derives MyContractA {...}

Answer

contract MyContractA extends MyContractB {...}

Answer

contract MyContractA inherit (MyContractB) {...}

Question 7

Without making a function call, you can send ether to a contract by:

Accepted Answer

A fallback function needs to be declared and paid for. An exception will be thrown if there is no fallback function or if the fallback function is not payable.

Answer

There is either no fallback function at all or there is a fallback function that is payable.

Answer

You must explicitly invoke a function before sending ether to a contract. It is impossible for the fallback function to get ether.

Question 8

It is impossible to employ inheritance from several sources in Solidity.

Accepted Answer

True

Answer

False

Answer

Sometimes

Answer

None of the above

Question 9

Metadata is generated when Solidity is compiled.

Accepted Answer

The ABI Array, which specifies the interface to communicate with the smart contract, is present in the metadata. The address of the smart contract when it is deployed may also be included in metadata.

Answer

A migration tool that installs the smart contract on the blockchain creates the ABI array and metadata, not Solidity when it is compiled to bytecode.

Answer

The address and size of the smart contract are contained in the metadata. When the smart contract is deployed, an external generator produces the ABI Array.

Question 10

Assert is used to?

Accepted Answer

Check internal conditions that ought to never occur

Answer

To examine user input arguments

Answer

To run programs internally