D
A- Harvard university professor
1/8=(1/2)^3 and the half life of radon is 3.8days
Half life is the time it takes for half of any amount of a radioactive substance to decay into something else.
Therefore for a sample of radon to decay to 1/8 of its original amount, it would take 3 x 3.8days=11.4 days
Protons, neutrons, and electrons.
The answer is A. The vibration caused by the waves through the air eventually weaken, which is why sound diminishes easily over distance.
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