Blockchain and Crypto DeFi & Smart Contracts 2

Question 1

What programming language is primarily used to write Ethereum smart contracts?

Accepted Answer

Solidity

Answer

Solidity is the primary programming language used to write smart contracts on the Ethereum blockchain, designed specifically for the EVM.

Question 2

What is the Ethereum Virtual Machine (EVM)?

Accepted Answer

The runtime environment that executes smart contract bytecode on Ethereum nodes

Answer

The EVM is the runtime environment that executes smart contract bytecode on all Ethereum nodes, ensuring consistent results across the network.

Question 3

What is a reentrancy attack in smart contracts?

Accepted Answer

A vulnerability where a contract is repeatedly called before its initial execution finishes

Answer

A reentrancy attack occurs when a malicious contract repeatedly calls back into a vulnerable contract before execution completes, allowing funds to be drained.

Question 4

What does 'gas' refer to in Ethereum transactions?

Accepted Answer

The computational fee required to execute transactions and smart contracts

Answer

Gas in Ethereum is the computational fee required to execute transactions or smart contracts, priced in gwei based on network demand.

Question 5

What is a blockchain oracle?

Accepted Answer

A service that provides external real-world data to smart contracts

Answer

A blockchain oracle is a service that provides external, real-world data to smart contracts, bridging the gap between on-chain code and off-chain information.

Blockchain and Crypto Practice Test

Blockchain and Crypto Practice Test

Blockchain and Crypto DeFi & Smart Contracts 2