what is the half - life of the radioactive substance below? select the best option.

Explanation:

Step1: Identify half - life concept

Half - life is when the amount of substance is half of the initial amount. Initial amount is 100%, half is 50%.

Step2: Locate 50% on the graph

Find the time when % of unstable isotopes remaining is 50% on the graph.

Step3: Read the time value

From the graph, when % of unstable isotopes remaining is 50%, the time is 4 minutes.

Answer:

4 min