CBCP Ethereum 2

Question 1

What is the purpose of the Ethereum Virtual Machine (EVM) opcode SLOAD?

Accepted Answer

Load a value from contract storage into the stack

Answer

SLOAD reads a 32-byte word from the contract's persistent storage slot into the execution stack.

Question 2

Which Ethereum upgrade introduced the concept of 'difficulty bomb' to encourage migration to Proof of Stake?

Accepted Answer

Byzantium

Answer

Byzantium (2017) included EIP-649, which delayed the difficulty bomb and reduced block rewards from 5 to 3 ETH.

Question 3

In Ethereum's account model, what differentiates an Externally Owned Account (EOA) from a contract account?

Accepted Answer

EOAs have no associated code and are controlled by private keys

Answer

EOAs have no code field and are controlled exclusively by whoever holds the corresponding private key.

Question 4

What does the Ethereum Yellow Paper define as the 'world state'?

Accepted Answer

A mapping of addresses to account states including balance, nonce, storage, and code

Answer

The world state is a Merkle Patricia Trie that maps 20-byte addresses to account state objects.

Question 5

Which EIP introduced the 'BASEFEE' opcode, allowing contracts to read the base fee of the current block?

Accepted Answer

EIP-3198

Answer

EIP-3198 added the BASEFEE opcode so smart contracts can access the current block's base fee directly.

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