You've experienced convection cooling if you've ever extended your hand out the window of a moving vehicle or into a flowing water stream. with the surface of your hand at a temperature of 30 degree c. determine the convection heat flux for a vehicle speed of 35 km/h in air at -5 degree c with a convection coefficient of 40 w/m2 . k and a velocity of 0.2 m/s in a water stream at 10 degree c with a convection coefficient of 900 w/m2 k. which condition would feel colder? contrast these results with a heat loss of approximately 30 w/m2 under normal room conditions.

Antireflective coatings on solar cells are often made by applying a thin film of silicon nitride (sinx), which has an index of refractive of 1.2, on the top of the silicon solar cell, which has a refractive index of about 3.5. however, the sun emits radiation of various wavelengths which the solar cell absorbs, and the antireflective coating can only absolutely minimize the reflection of one of these wavelengths. the coating thickness is chosen to reduce the reflection of green/yellow light (e = 2.2 ev), which is the most intense color in the solar spectrum (shown below). which of the following coatings would minimize reflection of green/yellow light? the answer is 820 nm how? what is the angular width of the central maximum of an electron traveling at 2 x 108 m/s going through a single slit of width 1 mm.