The activity of a sample of radioactive material `A_(1)` at time `t_(1)` and `A_(2)` at time `t_(2)(t_(2)gtt_(1))`. Its mean life is `T`.

The activity of a sample of a radioactive material is A_(1) at time t_(1) and A_(2) at time t_(2) , ( t_(2) gt t_(1)) . Its mean life is T. Then ______ .

The activity of a sample of radioactive material is R_(1) at time t_(1)andR_(2)"at time"t_(2)(t_(2)gtt_(1)) . Its mean life is T. Then,

The activity of a sample of radioactive material is R_(1) at time t_(1)andR_(2)"at time"t_(2)(t_(2)gtt_(1)) . Its mean life is T. Then,

The activity of a sample of a radioactive meterial is A_1 , at time t_1 , and A_2 at time t_2(t_2 gt t_1) . If its mean life T, then

The activity of a sample of a radioactive meterial is A_1 , at time t_1 , and A_2 at time t_2(t_2 gt t_1) . If its mean life T, then

The activity of a sample of radioactive material is A_1 at time t_(1) and A_(2) at time t_(2)(t_(2) le t_(1)) . Obtain an expression for its mean life.

The activity of a sample of radioactive material is A_1 at time t_1 and A_2 at time t_(2)(t_2 gt t_1) . Obtain an expression for its mean life.

The activity of a radioactive substance is R_(1) at time t_(1) and R_(2) at time t_(2)(gt t_(1)) . Its decay cosntant is lambda . Then .

The activity of a radioactive substance is R_(1) at time t_(1) and R_(2) at time t_(2)(gt t_(1)) . Its decay cosntant is lambda . Then .

Activity of a radioactive substance is R_(t) at time t_(1) and R_(2) at time t_(2)(t_(2)gtt_(1)) . Then the ratio (R_(2))/(R_(1)) is