Answer:
1.5625g would remain after 30 seconds
Step-by-step explanation:
When we talk about half life, we are talking about the time taken for exactly half of the mass of the radioactive mass in question to have disintegrated.
More like, the amount of time it takes for the radioactive mass to have lost exactly half of its mass
Now, the half life of the substance in question is 6 seconds and we have to calculate the mass that would remain after 30 seconds. What this means is that we would have a disintegration of 5 times, meaning 5 half lives.
Since it is just 5 half lives, we can proceed manually
In the first, we shall have 25g left
in the second, we shall have 12.5g left
In the third, we shall have 6.25g left
In fourth, we shall have have 3.125g left
and finally, in the fifth, we shall have 1.5625g
