Ethereum Smart Contracts Guide Quiz

1. What is Ethereum?

• Ethereum is a video game that simulates trading and investing.
• Ethereum is a social media platform for sharing financial tips.
• Ethereum is an open-source, decentralized blockchain platform that allows developers to create decentralized applications (dApps) and smart contracts.
• Ethereum is a type of cryptocurrency used exclusively for online shopping.

2. What are smart contracts?

• Smart contracts are only for cryptocurrency transactions.
• Smart contracts are physical contracts stored in a bank.
• Smart contracts are legal documents signed by parties.
• Smart contracts are self-executing programs on the blockchain.

3. What programming language is used to write Ethereum smart contracts?

• Ruby
• Python
• JavaScript
• Solidity

4. What is the purpose of setting up the development environment for Ethereum smart contracts?

• The purpose is to audit the security of existing smart contracts on the network.
• The purpose is to create a user interface for the smart contract functionality.
• The purpose is to install the necessary tools and libraries, including a text editor, an Ethereum node, and the Solidity compiler.
• The purpose is to gather community feedback on the effectiveness of the smart contracts.

5. What is the first step in developing an Ethereum smart contract?

• Write the smart contract code.
• Set up the development environment.
• Deploy the smart contract directly.
• Test the smart contract functions.

6. What is the role of the Solidity compiler in Ethereum smart contract development?

• The Solidity compiler validates the Ethereum network transactions.
• The Solidity compiler stores the smart contract data in the blockchain.
• The Solidity compiler executes the smart contracts on the blockchain.
• The Solidity compiler generates the bytecode for the smart contract.

7. What is the bytecode in Ethereum smart contract development?

• The bytecode is the transaction history of the smart contract.
• The bytecode is the low-level representation of the smart contract and is not human-readable.
• The bytecode is the user interface for interacting with smart contracts.
• The bytecode is a programming language used to create smart contracts.

8. How is a smart contract deployed to the Ethereum blockchain?

• A smart contract is deployed by sending a transaction to the Ethereum network that includes the bytecode for the smart contract.
• A smart contract is deployed by creating a new Ethereum wallet for each contract.
• A smart contract is deployed by editing the Ethereum node configuration file.
• A smart contract is deployed by using a centralized server to host the contract.

9. What is the importance of testing in Ethereum smart contract development?

• Testing is important to ensure the smart contract works as expected and to identify and fix any bugs or errors in the code.
• Testing is only required for traditional software, not for smart contracts on Ethereum.
• Testing is unnecessary because smart contracts are always correct without verification.
• Testing is performed only after deployment to check contract interactions.

10. How can you interact with an Ethereum smart contract?

• You can interact with a smart contract using a web3.js library, which provides an interface for interacting with the Ethereum blockchain.
• You can interact with a smart contract by calling it via email attachment.
• You can interact with a smart contract by posting on social media.
• You can interact with a smart contract by sending a letter to its address.

11. What are the types of accounts on Ethereum?

• Wallet Accounts and Exchange Accounts
• User Accounts and System Accounts
• Personal Accounts and Business Accounts
• Externally Owned Accounts (EOAs) and Contract Accounts

12. What is a nonce in Ethereum?

• A nonce is a network protocol used to connect Ethereum nodes.
• A nonce is a sequence number issued by the originating EOA to prevent message replay.
• A nonce is a type of cryptocurrency used for transactions.
• A nonce is a unique identifier for each block in the blockchain.

13. How are miners incentivized to validate and create new blocks on Ethereum?

• Miners are paid in advertisements displayed during transactions.
• Miners are incentivized by block rewards and transaction fees.
• Miners earn points which can be redeemed for rewards later.
• Miners are compensated by fixed salaries from the network.

14. Can anyone deploy a smart contract on Ethereum?

• Only authorized developers can deploy a smart contract on Ethereum.
• Yes, anyone can deploy a smart contract on Ethereum.
• Smart contracts can only be deployed by enterprise users.
• Only users with high balances can deploy a smart contract on Ethereum.

15. What is the difference between Bitcoin and Ethereum?

• Bitcoin is faster for transactions and has lower fees.
• Bitcoin has a larger market cap than Ethereum does.
• Ethereum is only a digital currency, while Bitcoin is a platform.
• The differences include smart contract support, UTXO vs accounts, and underlying tokens (Bitcoin vs Ether).

16. What are the high-level languages typically used for writing Ethereum smart contracts?

• Python and Java
• C++ and Ruby
• Rust and Go
• Solidity and Vyper

17. How do Ethereum nodes communicate with each other?

• Ethereum nodes communicate only through direct connections.
• Ethereum nodes communicate using centralized servers.
• Ethereum nodes communicate via a peer-to-peer network.
• Ethereum nodes communicate via email.

18. What is the number of decimals in Ether?

• 16
• 18
• 20
• 10

19. What is the structure of a smart contract?

• The structure includes variables, functions, and events defined in the contract.
• The structure is made up of steps, sequences, and processes in project management.
• The structure involves layers, nodes, and connections in a network topology.
• The structure consists of styles, colors, and fonts used in designs.

20. What are the key components of a smart contract?

• The key components include the title, description, terms, and signatures in written format.
• The key components include parties involved, date, terms of agreement, and witness signatures.
• The key components include name, symbol, decimals, total supply, balanceOf, allowance, Transfer, and Approval events.
• The key components include header, body, footer, and signature of a legal document.

21. How do you compile and deploy a smart contract using Truffle?

• You first write the contract, then run `npm start` to deploy it automatically.
• You write the contract, save it to a text file, and email it to a developer for deployment.
• You compile by running `truffle start`, then upload it to a server.
• You compile and deploy using `npm install -g truffle`, `truffle init`, and deploying scripts in the migrations directory.

22. What is the purpose of the `require` statement in Solidity?

• The purpose is to initialize the Ethereum node connection for deployment.
• The purpose is to declare variables and their types within the contract.
• The purpose is to store user data for transaction processing.
• The purpose is to manage exceptions and ensure contract integrity by checking conditions before executing code.

23. How do you send a transaction to a smart contract?

• You send a transaction by calling external services to send messages.
• You send a transaction by creating a new Ethereum account for the contract.
• You send a transaction by specifying the contract address, encoded function call, parameters, value, and gas.
• You send a transaction by writing the contract code directly into the blockchain.

24. What is the role of gas in sending transactions to smart contracts?

• Gas is the time limit for executing a smart contract.
• Gas is the number of transactions processed in a block.
• Gas is the maximum amount of computational effort allowed for the transaction.
• Gas is the currency used for paying fees on the blockchain.

25. What are the common functions in a token smart contract?

• The common functions include transfer, approve, and transferFrom.
• The common functions include create, delete, and modify.
• The common functions include fetch, send, and display.
• The common functions include build, shape, and expand.

26. How do you interact with a deployed smart contract using ethers.js?

• You interact by compiling the contract and then executing it on the local server.
• You interact by sending a simple JSON request to the blockchain node.
• You interact by writing JavaScript directly in the Ethereum wallet.
• You interact by creating a new ethers.Contract instance and calling functions on it.

27. What is the significance of the `emit` keyword in Solidity?

• The `emit` keyword is used to declare variables in Solidity.
• The `emit` keyword is used to send Ether from one address to another.
• The `emit` keyword is used to define state changes in the smart contract.
• The `emit` keyword is used to log events on the blockchain.

28. What are the common types of smart contracts?

• Basic, advanced, and modular smart contracts.
• Direct, indirect, and reflexive smart contracts.
• Static, dynamic, and transitional smart contracts.
• Simple, complex, and hybrid smart contracts.

29. What are the use cases for smart contracts?

• The use cases include creating artwork, enhancing gaming graphics, and developing mobile applications.
• The use cases include cooking recipes, making shopping lists, and planning vacations.
• The use cases include designing websites, printing photos, and organizing events.
• The use cases include automating processes, facilitating asset exchange, and managing complex transactions.

30. How do smart contracts ensure security?

• Smart contracts ensure security through the use of `require` statements, assertions, and reverts to manage exceptions and ensure contract integrity.
• Smart contracts ensure security by using a centralized database and manual checks to verify transactions.
• Smart contracts ensure security by requiring physical signatures and notarization of agreements before execution.
• Smart contracts ensure security by allowing users to modify existing contracts at any time without restrictions.