Siruis, the brightest star in the night sky, has a luminosity of 22. This means that Sirius: A, B, C, D QUESTION A: developed 22 years before the sun
B: is 22 times farther from Earth than the sun
C: gives off 22 times more energy than the sun
D: is 22 times bigger in size than the sun

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 i0 of the incident beam. what is the intensity of the beam "10" feet below the surface? (give your answer in terms of i0. round any constants or coefficients to five decimal places.)