Question

A certain radioactive substance has half-life of 5 years. Thus, for a nucleus in a sample of the element, the probability of decay in ten years is:

• A. 50%
• B. 75%
• C. 100%
• D. 60%

Answer 1

Answer: (B)

75%

Answer 2

Prob. of decay = 1 –$\frac { 1 } { 2 ^ { 2 } }$ = 3/4 = 75%