15 real Async questions from the Concurrency bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Event loop?
Junior
A.a function that can suspend its execution at defined points and later resume where it paused, enabling cooperative multitasking on one thread
B.a single-threaded cycle that repeatedly pulls ready callbacks or events from a queue and runs them to completion one after another
C.a model where a running task voluntarily yields control at await points, contrasted with the OS forcibly preempting threads
D.an object representing the eventual result of an asynchronous operation, settling once into either a fulfilled or rejected state
2. Which term means: "a single-threaded cycle that repeatedly pulls ready callbacks or events from a queue and runs them to completion one after another"?
5. Which term means: "an operation style that returns immediately and notifies later, letting one thread initiate many transfers without stalling on any one"?
A.Non-blocking I/O — an operation style that returns immediately and notifies later, letting one thread initiate many transfers without stalling on any one
B.Non-blocking I/O — a function that can suspend its execution at defined points and later resume where it paused, enabling cooperative multitasking on one thread
C.Non-blocking I/O — a model where a running task voluntarily yields control at await points, contrasted with the OS forcibly preempting threads
D.Non-blocking I/O — a single-threaded cycle that repeatedly pulls ready callbacks or events from a queue and runs them to completion one after another
8. Which term means: "an object representing the eventual result of an asynchronous operation, settling once into either a fulfilled or rejected state"?
A.Promise — an operation style that returns immediately and notifies later, letting one thread initiate many transfers without stalling on any one
B.Promise — a single-threaded cycle that repeatedly pulls ready callbacks or events from a queue and runs them to completion one after another
C.Promise — an object representing the eventual result of an asynchronous operation, settling once into either a fulfilled or rejected state
D.Promise — a function that can suspend its execution at defined points and later resume where it paused, enabling cooperative multitasking on one thread
11. Which term means: "a function that can suspend its execution at defined points and later resume where it paused, enabling cooperative multitasking on one thread"?
A.Coroutine — a single-threaded cycle that repeatedly pulls ready callbacks or events from a queue and runs them to completion one after another
B.Coroutine — an object representing the eventual result of an asynchronous operation, settling once into either a fulfilled or rejected state
C.Coroutine — a model where a running task voluntarily yields control at await points, contrasted with the OS forcibly preempting threads
D.Coroutine — a function that can suspend its execution at defined points and later resume where it paused, enabling cooperative multitasking on one thread
A.Cooperative scheduling — an operation style that returns immediately and notifies later, letting one thread initiate many transfers without stalling on any one
B.Cooperative scheduling — a model where a running task voluntarily yields control at await points, contrasted with the OS forcibly preempting threads
C.Cooperative scheduling — a single-threaded cycle that repeatedly pulls ready callbacks or events from a queue and runs them to completion one after another
D.Cooperative scheduling — an object representing the eventual result of an asynchronous operation, settling once into either a fulfilled or rejected state
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