Answer:
The correct answer is - 15 hours.
Step-by-step explanation:
Half-life an element is the time required to decay the half amount of the initial amount of the element and is represented by t1/2.
The formula for the calculating initial amount
n(i)=n(r)⋅2^n
where
n(i) - the initial number of moles of element
n(r) - the number of moles remained amount after the given time
n - the number of periods,
= time T, where T is the half-life.
n(i)=n(r)⋅2^n
n(i)/n(r) =2^n
1/16 =2^n
n= 4
The half life = 60/n
= 60/4
= 15 hours.