Question

A radioactive sample is undergoing α decay. At any time t₁, its activity is A and another time t₂, the activity is `"A"/5`. What is the average life time for the sample?

Options

• `("t"_2 - "t"_1)/(ln 5)`

• `(ln ("t"_2 + "t"_1))/2`

• `(ln 5)/("t"_2 - "t"_1)`

• `("t"_1 - "t"_2)/ln 5`

Answer 1

`("t"_1 - "t"_2)/ln 5`