Lep pozdrav!
Lepo prosim vsakega, ki bi znal rešiti naslednji 2 nalogi. Ker sem na izmenjavi, prilegam tekst v angleščini.
1.
When an acoustic plane wave is reflected from a fluid‐fluid interface it is observed that
at normal incidence the pressure amplitude of the reflected wave is 1/2 that of the
incident wave. At an angle of 30°, the reflected wave is as strong as the incident wave.
What is the density and sound speed in the second medium if the first medium is water?
(Hint: The acoustic impedance of water is 1.48 MRayl)
2.
Assume an infinitely broad light beam with a wavelength of 750nm hits a sample of biological
tissue with a thickness of 2cm. Calculate the I/I0
attenuation a light beam making realistic assumptions on the reduced
scattering coefficient µs’ and the absorption coefficient µa
of an assumed tissue at this
wavelength. How would the calculation change if you had a focused laser beam? Why? Please
calculate the attenuation for a point laser beam as well showing all the equations and
assumptions that you used.