# The half life of radon-222 is 3.824 days. After what time will one fourth of a given amount of radon remain?

Jun 2, 2017

Decay process. After 7.648 days, you will see one quarter.

#### Explanation:

$1 \to 0.5 \to 0.25$

From one full unit to one quarter, you need two periods (arrows Show one period or half life). Since half life of radon-222 is 3.824 days, you need twice this time to get one quarter at the end.

$2 \cdot 3.824 = 7.648$ days.

You require 7.648 days to reach one quarter at the end.