PPT Slide

program Radioactive_Decay

!----------------------------------------------------------------------------

! This program calculates the amount of a radioactive substance that

! remains after a specified time, given an initial amount and its

! half-life. Variables used are:

! InitalAmount : initial amount of substance (mg)

! HalfLife : half-life of substance (days)

! Time : time at which the amount remaining is calculated (days)

! AmountRemaining : amount of substance remaining (mg)

! Input: InitialAmount, HalfLife, Time

! Output: AmountRemaining

!-----------------------------------------------------------------------------

implicit none

real :: InitialAmount, HalfLife, Time, AmountRemaining

! Get values for InitialAmount, HalfLife, and Time.

print *, "Enter initial amount (mg) of substance, its half-life (days)"

print *, "and time (days) at which to find amount remaining:"

read *, InitialAmount, HalfLife, Time

! Compute the amount remaining at the specified time.

AmountRemaining = InitialAmount * 0.5 ** (Time / HalfLife)

! Display AmountRemaining.

print *, "Amount remaining =", AmountRemaining, "mg"

end program Radioactive_Decay