1. A sunphotometer is an instrument that looks at visible light coming in a straight line directly from the sun with F0= 1850 W/m²/um. At one point with cloudy sky and aerosol plume under the cloud, it measures an irradiance of I1 W/m²/um. When the cloud passes this increases to I2 W/m²/um and when there were no aerosols, the irradiance became 13 W/m²/um. Assuming sun zenith angle 0 degrees: a) What is the optical depth of the cloud? b) If the cloud would be twice thinner, what intensity would the sunphotometer measures when the cloud was overhead? What is the transmittance for this case? c) What are the optical thicknesses of aerosol and Rayleigh scattering components?

A mirror produces an image that is located 41.0 cm behind the mirror, when the object is located 5.60 cm in front of the mirror. (a) What is the focal length of the mirror? (b) Is the mirror concave or convex? (a) Number i (b) Units

1. Calculate the surface per unit volume in square centi- meters per cubic centimeter of galena having the screen analysis below. Use the method of extrapolation for -200 mesh, and assume that the two points between 100 and 200 mesh determine the straight line in a log-log plot. Specific gravity of galena = 7.43. Mesh 3 + 4 4 + G 6+8 8 + 10 10+14 14 + 20 20 + 28 28 + 35 35 + 48 48 + 65 65 +100 -100 +150 -150 +200 -200 - 1 - - - - - Percentage Retained 1.0 4.0 8.1 11.5 16.0 14.8 13.2 8.1 6.2 4.1 3.6 2.2 1.9 5.3

Reynolds analogy is preferred over Chilton-Colburn analogy. True False Depends on Sh Only for flat plate Depends on P