X-rays with a wavelength of 0.0711 nm create a diffraction pattern when they pass through a protein crystal. if the angular spacing between adjacent bright spots (m=0 and m=1) in the diffraction pattern is 28.9°, what is the average spacing between atoms in the crystal?

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.)