How long will a radioactive isotope decay?

Until there's none of it left. Different radioactive isotopes decay at different rates. And a bigger pile of it will last longer than a smaller pile. Without knowing WHICH radioactive isotope you're asking about, and how much of it you started out with, the answer could turn out to be anywhere between 1 millionth of a second and 1 million years.

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explanation:

wind is defined by the direction it blows from.   for example, a wind blowing from north to south is called a northerly wind.

absorption lines are where light has been absorbed by the atom thus you see a dip in the spectrum whereas.

emission spectra have spikes in the spectra due to atoms releasing photons at those wavelengths.

explanation: