[0/1 Points] ZILLDIFFEQMODAP12 3.1.011.EP. When a vertical beam of light passes through a transparent medium, the rate at which its intensity
I
decreases is proportional to
I(t)
, where
t
represents the thickness of the medium (in feet). In clear seawater, the intensity 3 feet below the surface is
25%
of the initial intensity
I_(0)
of the incident beam. Find the constant of proportionality
k
, where
(dI)/(dt)=kI
.
k=
What is the intensity of the beam 13 feet below the surface? (Give your answer in terms of
I_(0)
. Round any constants or coefficients to five decimal places.)