Crypto Jobs Blockchain Fundamentals 3

Question 1

What is a smart contract?

Accepted Answer

Self-executing code on a blockchain that runs when conditions are met

Answer

Smart contracts are programs deployed on-chain that automatically execute predefined logic when triggered.

Question 2

What is 'gas' on a network like Ethereum?

Accepted Answer

The fee paid to compensate for computational work

Answer

Gas measures and prices the computational effort required to execute operations, paid to validators.

Question 3

What is the difference between a public and a private blockchain?

Accepted Answer

Public chains allow anyone to participate while private chains restrict access

Answer

Public blockchains are permissionless and open, whereas private (permissioned) chains limit who can read or validate.

Question 4

What is a cryptographic hash function expected to do?

Accepted Answer

Produce a fixed-length, deterministic output that is hard to reverse

Answer

A good hash function is deterministic, one-way, and collision-resistant, producing fixed-length digests.

Question 5

What problem does the 'double-spending' issue describe?

Accepted Answer

Spending the same digital coin more than once

Answer

Double-spending is the risk of using the same units twice, which consensus and confirmations prevent.

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