Honed I don’t know where the question is
I think because water gives pressure and if u go even deeper theres more pressure
<u>Answer:</u> The remaining sample of X is 6.9 grams.
<u>Explanation:</u>
All the radioactive reactions follow first order kinetics.
The equation used to calculate rate constant from given half life for first order kinetics:

We are given:

Putting values in above equation, we get:

The equation used to calculate time period follows:

where,
= initial mass of sample X = 78 g
N = remaining mass of sample X = ? g
t = time = 16.5 min
k = rate constant = 
Putting values in above equation, we get:

Hence, the remaining amount of sample X is 6.9 g
it is known as the
nuclear meltdown
Joule (J) is the metric unit for energy