Question

What part of second is called nanosecond

Answer 1

one thousand-millionth of a second.

informal

a very short time; a moment.

"she can flick between manic laughter and tears in a nanosecond"

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Answer 2

it is the one thousand-millionth part of asecond  in mathematical way it si 10−9 or 1/1,000,000,000 s part of a second. One nanosecond is to one second as one second is to 31.71 years.

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